Pressed and Self Sintered Polymer Derived SiC Materials, Applications and Devices

ABSTRACT

Organosilicon chemistry, polymer derived ceramic materials, and methods. Such materials and methods for making polysilocarb (SiOC) and Silicon Carbide (SiC) materials having 3-nines, 4-nines, 6-nines and greater purity. Processes and articles utilizing such high purity SiOC and SiC.

This application: (i) claims under 35 U.S.C. § 119(e)(1) the benefit ofthe filing date of Sep. 25, 2014 of U.S. provisional application Ser.No. 62/055,397; (ii) claims under 35 U.S.C. § 119(e)(1) the benefit ofthe filing date of Sep. 25, 2014 of U.S. provisional application Ser.No. 62/055,461; (iii) claims under 35 U.S.C. § 119(e)(1) the benefit ofthe filing date of Sep. 25, 2014 of U.S. provisional application Ser.No. 62/055,497; (iv) claims under 35 U.S.C. § 119(e)(1) the benefit ofthe filing date of Feb. 4, 2015 of U.S. provisional application Ser. No.62/112,025; (v) is a continuation in part of U.S. patent applicationSer. No. 14/268,150 filed May 2, 2014, which claims, under 35 U.S.C. §119(e)(1), the benefit of the filing date of May 2, 2013 of U.S.provisional application Ser. No. 61/818,906 and the benefit of thefiling date of May 3, 2013 of U.S. provisional application Ser. No.61/818,981; (vi) is a continuation-in-part of U.S. patent applicationSer. No. 14/634,814 filed Feb. 28, 2015, which claims under 35 U.S.C. §119(e)(1) the benefit of the filing date of Feb. 28, 2014 of U.S.provisional application Ser. No. 61/946,598; and (vii) is a continuationin part of U.S. patent application Ser. No. 14/212,896, filed Mar. 14,2014, the entire disclosures of each of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION Field of the Invention

The present inventions relate to polyorganic compositions, methods,structures and materials; polymer derived preceramic and ceramicmaterials and methods; and in particular polysilocarb compositions,methods, structures and materials. The present inventions further relateto methods for making Silicon Carbide (SiC) and SiC compositions,structures, components, materials and apparatus for making these items;methods for making Silicon Carbide (SiC) and SiOC compositions,structures, components, materials and apparatus for making these items;and in particular, to SiC that is made from polysilocarb materials.Polysilocarb materials and methods of making those materials aredisclosed and taught in U.S. patent application Ser. Nos. 14/212,896,14/324,056, 14/268,150 and 14/634,819, the entire disclosures of each ofwhich are incorporated herein by reference.

Materials made of, or derived from, carbosilane or polycarbosilane(Si—C), silane or polysilane (Si—Si), silazane or polysilazane(Si—N—Si), silicon carbide (SiC), carbosilazane or polycarbosilazane(Si—N—Si—C—Si), siloxane or polysiloxanes (Si—O) are known. Thesegeneral types of materials have great, but unrealized promise; and havefailed to find large-scale applications or market acceptance. Instead,their use has been relegated to very narrow, limited, low volume, highpriced and highly specific applications, such as a ceramic component ina rocket nozzle, or a patch for the space shuttle. Thus, they havefailed to obtain wide spread use as ceramics, and it is believed theyhave obtained even less acceptance and use for other applications.

To a greater or lesser extent all of these materials and the processused to make them suffer from one or more failings, including forexample: they are exceptionally expensive and difficult to make, havingcosts in the thousands and tens-of-thousands of dollars per pound; theyrequire high and very high purity starting materials; the process ingeneral fails to produce materials having high purity; the processrequires hazardous organic solvents such as toluene, tetrahydrofuran(THF), and hexane; the materials are incapable of making non-reinforcedstructures having any usable strength; the process produces undesirableand hazardous byproducts, such as hydrochloric acid and sludge, whichmay contain magnesium; the process requires multiple solvent and reagentbased reaction steps coupled with curing and pyrolizing steps; thematerials are incapable of forming a useful prepreg; and their overallphysical properties are mixed, e.g., good temperature properties buthighly brittle.

As a result, although believed to have great promise, these types ofmaterials have failed to find large-scale applications or marketacceptance and have remained essentially scientific curiosities.

Silicon carbide (SiC), is a compound of silicon (Si) and carbon (C) thathas wide ranging uses, applications and potential for future uses.Eugene Acheson is generally credited with developing the firstcommercial processes for making silicon carbide, which are taught anddisclosed in U.S. Pat. Nos. 492,767 and 560,291, the entire disclosuresof each of which are incorporated herein by reference. Silicon carbideis a highly versatile material. Silicon carbide can have several forms,e.g., amorphous, crystalline having many different polytypes, andforming single (or mono-) and polycrystalline structures. Siliconcarbide finds applications in among other things, abrasives, frictionmembers, and electronics. Silicon carbide powder, fines, pellets, orother smaller sized and shaped forms, can be joined together by way of asintering operation to form component parts and structures.

Generally, silicon carbide can function as a semiconductor. As amaterial it very stable. Silicon carbide is a very hard material. It isessentially chemically inert, and will not react with any materials atroom temperature.

In recent years the demand for high purity silicon carbide, and inparticular high purity single crystalline carbide materials for use inend products, such as a semiconductor, has been increasing, but isbelieve to be unmet. For example, “single crystals are gaining more andmore importance as substrate[s] for high frequency and high powersilicon carbide electronic devices.” Wang, et. al, Synthesis of HighPower Sic Powder for High-resistivity SiC Single crystals Growth, p. 118(J. Mater. Sic. Technol. Vol. 23, No 1, 2007)(hereinafter Wang). Toobtain these high purity silicon carbide end products, silicon carbidepowder as a starting or raw material must be exceedingly pure. However,“[c]ommercially available SiC powder is usually synthesized bycarbothermal reduction of silica. Unfortunately, it is typicallycontaminated to the level that makes it unsuitable for SiC growth.”Wang, at p. 118.

The longstanding need for, and problem of obtaining high purity siliconcarbide, and the failing of the art to provide a viable (both from atechnical and economical standpoint) method of obtaining this materialwas also recognized in Zwieback et al., 2013/0309496 (“Zwieback”), whichprovides that the “[a]vailability of high-purity SiC source material isimportant for the growth of SiC single crystals in general, and it iscritical for semi-insulating SiC crystals” (Zwieback at ¶ 0007).Zwieback goes on to state that the prior methods including liquid basedmethods have consistently failed to meet this need: “While numerousmodifications of the Acheson process have been developed over the years,the produced SiC material always contain high concentrations of boron,nitrogen aluminum and other metals, and is unsuitable as a sourcematerial for the growth of semiconductor-quality SiC crystals” (Zwiebackat ¶ 0009); “commercial grade bulk SiC produced by CVD is not pureenough for the use as a source in SiC crystal growth” (Zwieback at ¶0010); the liquid process “produced SiC material contains largeconcentrations of contaminates and is unsuitable for the growth ofsemiconductor-quality SiC crystals” (Zwieback at ¶ 0011); and, thedirect synthesis of SiC provides an impure material that “precludes theuse of such material” (Zwieback at ¶ 0015). Zwieback itself seeks toaddress this long-standing need with a complex, multi-step version ofwhat appears to be the direct process in a stated attempt to providehigh purity SiC. It is believed that this process is neither technicallyor economically viable; and therefor that it cannot solve thelongstanding need to provide commercial levels of high purity SiC.

Thus, although there are other known methods of obtaining siliconcarbide, it is believed that none of these methods provide the requisitetechnical, capacity, and economical viability to provide the puritylevels, amounts, and low cost required for commercial utilization andapplications; and in particular to meet the ever increasing demands forsemiconductor grade material, and other developing commercialutilizations and applications. “Among these synthesis methods, only CVDhas been successfully used to produce high purity SiC powder, it is notsuitable for mass production because of high costs associated with CVDtechnology.” Wang, at p. 118.

CVD generally refers to Chemical Vapor Deposition. CVD is a type ofvapor deposition technology. In addition to CVD, vapor depositiontechnologies would include PVD (Physcial Vapor Deposition), plasmaenhanced CVD, Physical Vapor Transport (PVT) and others.

Thus, for these end products, and uses, among others that require highpurity materials, there is an ever increasing need for low cost siliconcarbide raw material that has a purity of at least about 99.9%, at leastabout 99.99%, at least about 99.999%, and least about 99.9999% and atleast about 99.99999% or greater. However, it is believe that prior toembodiments of the present inventions, for all practical purposes, thisneed has gone unmet.

Further, prior to embodiments of the present inventions, it is believedthat high purity and ultrahigh purity SiOC materials, and in particularin quantities larger than small laboratory batches of a few ounces, havenever been obtained, and thus their importance, benefits, and the needfor such material, has gone largely unrecognized and unappreciated.

High purity single crystalline silicon carbide material has manydesirable features and characteristics. For example, it is very hardhaving a Young's modulus of about 424 GPa. Polycrystalline siliconcarbide may also have very high hardness, depending upon its grainstructure and other factors.

As used herein, unless specified otherwise, the terms specific gravity,which is also called apparent density, should given their broadestpossible meanings, and generally mean weight per until volume of astructure, e.g., volumetric shape of material. This property wouldinclude internal porosity of a particle as part of its volume. It can bemeasured with a low viscosity fluid that wets the particle surface,among other techniques.

As used herein, unless specified otherwise, the terms actual density,which may also be called true density, should be given their broadestpossible meanings, and general mean weight per unit volume of amaterial, when there are no voids present in that material. Thismeasurement and property essentially eliminates any internal porosityfrom the material, e.g., it does not include any voids in the material.

Thus, a collection of porous foam balls (e.g., Nerf® balls) can be usedto illustrate the relationship between the three density properties. Theweight of the balls filling a container would be the bulk density forthe balls:

${{Bulk}\mspace{14mu} {Density}} = \frac{{weight}\mspace{14mu} {of}\mspace{14mu} {balls}}{{volume}\mspace{14mu} {of}\mspace{14mu} {container}\mspace{14mu} {filled}}$

The weight of a single ball per the ball's spherical volume would be itsapparent density:

${{Apparent}\mspace{14mu} {Density}} = \frac{{weight}\mspace{14mu} {of}\mspace{14mu} {one}\mspace{14mu} {ball}}{{volume}\mspace{14mu} {of}\mspace{14mu} {that}\mspace{14mu} {ball}}$

The weight of the material making up the skeleton of the ball, i.e., theball with all void volume removed, per the remaining volume of thatmaterial would be the actual density:

${{Actual}\mspace{14mu} {Density}} = \frac{{weight}\mspace{14mu} {of}\mspace{14mu} {material}}{{volume}\mspace{14mu} {of}\mspace{14mu} {void}\mspace{14mu} {free}\mspace{14mu} {material}}$

As used herein, unless stated otherwise, room temperature is 25° C. And,standard ambient temperature and pressure is 25° C. and 1 atmosphere.

Generally, the term “about” as used herein unless specified otherwise ismeant to encompass a variance or range of ±10%, the experimental orinstrument error associated with obtaining the stated value, andpreferably the larger of these.

SUMMARY

There has been a long-standing and unfulfilled need for, among otherthings, methods of making SiC, cost effective and reduced cost method ofmaking higher purity SiC, and devices, apparatus and equipment thatutilize SiC, and higher purity SiC. There has also been an unrecognized,but long-standing and unfulfilled need for, among other things, ultrahigh purity, e.g., 5-nines and greater SiOC ceramics, and for methods ofmaking these.

The present inventions, among other things, solve these needs byproviding the compositions, materials, articles of manufacture, devicesand processes taught, disclosed and claimed herein.

Thus, there is provided an article, the article including: a selfsintered polysilocarb derived silicon carbide composition; the selfsintered polysilocarb derived silicon carbide composition includingsintered submicron size silicon carbide particles, wherein thecomposition is substantially free from sintering aids.

Further, there are provided methods, compositions and articles havingone or more of the following features: wherein the polysilocarb has amolar ratio of about 30% to 85% carbon, about 5% to 40% oxygen, andabout 5% to 35% silicon; wherein the polysilocarb has a molar ratio ofabout 50% to 65% carbon, about 20% to 30% oxygen, and about 15% to 20%silicon; wherein the silicon carbide particles have impurities of lessthan about 100 ppm total of the elements selected from the groupconsisting of Al, Fe, B, P, Pt, Ca, Mg, Li, Na, Ni, V, Pr, Ce, Cr, S andAs; wherein the silicon carbide particles have impurities of less thanabout 10 ppm total of the elements selected from the group consisting ofAl, Fe, B, P, Pt, Ca, Mg, Li, Na, Ni, V, Pr, Ce, Cr, S and As; whereinthe silicon carbide particles have impurities of less than about 1 ppmtotal of the elements selected from the group consisting of Al, Fe, B,P, Pt, Ca, Mg, Li, Na, Ni, V, Pr, Ce, Cr, S and As; wherein the siliconcarbide particles are at least 99.999% pure; wherein the silicon carbideparticles are at least 99.9999% pure; wherein the silicon carbideparticles are at least 99.99999% pure; wherein the article is selectedfrom the group consisting of armor, ballistic materials, blast shields,penetration resistant materials, windows, lenses, fibers, internalreflection optics, total internal reflection optics, optics, brakerotors, brake assemblies, brake disks, brake pads, gemstones,semiprecious stones, and jewelry; and having a layer of material, thelayer including the self sintered polysilocarb derived silicon carbidecomposition.

Moreover, there is provided a silicon carbide composition including:polymer derived silicon carbide particles; the particles having a meanparticle size of about 0.5 μm or smaller; the particles consistingessentially of silicon and carbon in an SiC₄ configuration, wherein theparticles have less than 0.5% excess carbon, and are at least 99.99999%pure.

Still further there are provided methods, composition and articleshaving one or more of the following features: wherein the mean particlesize is about 0.2 μm or smaller; wherein the mean particle size is about0.1 μm or smaller.

Still further there is provided a self sinterable silicon carbidecomposition including: polymer derived silicon carbide particles; theparticles having a mean particle size of about 0.5 μm or smaller; theparticles consisting essentially of silicon and carbon in an SiC₄configuration, wherein the particles have less than 0.1% excess carbon,and are at least 99.99999% pure; wherein the particles are capable ofbeing formed into a solid SiC volumetric shape without the need for asintering aid.

Further, there are provided methods, compositions and articles havingone or more of the following features: wherein the volumetric shape is alayer; wherein the volumetric shape, is selected from the group ofshapes consisting of a window, a lens, and a fiber; and wherein thevolumetric shape is an article selected from the group consisting ofarmor, ballistic materials, blast shields, penetration resistantmaterials, windows, lenses, fibers, internal reflection optics, andoptics.

Additionally, there is provided a sinterable silicon carbide compositionincluding: a plurality of silicon carbide particles, the plurality ofparticles having a total weight of greater than at least about 10 grams;the particles having a mean particle size of about 0.5 μm or smaller;the composition consisting essentially of silicon and carbon in an SiC₄configuration, wherein the particles have less than 0.5% excess carbon,and are at least 99.99999% pure; wherein the particles are capable ofbeing sintered into a solid SiC article without the need for a sinteringaid, the sintered SiC article having at least one strength properties atleast 90% as strong as elemental SiC.

In addition there is provided a silicon carbide composition including:polymer derived silicon carbide particles; the particles having a meanparticle size of about 0.5 μm or smaller, each particle having asurface, wherein the surfaces are free from an oxide layer; theparticles consisting essentially of silicon and carbon, wherein theparticles have less than 0.5% excess carbon, and are at least 99.99999%pure.

Moreover, there is provided a silicon carbide composition including:polymer derived silicon carbide particles; the particles having aparticle size smaller than about 5 μm, each particle having a surface,wherein the surfaces are free from an oxide layer; and, the particlesconsisting essentially of SiC, wherein the particles are at least99.99999% pure.

Further, there are provided methods, compositions and articles havingone or more of the following features: wherein the particle size issmaller than about 1 μm; wherein the particle size is smaller than about0.5 μm; wherein the particle size is smaller than about 0.1 μm; whereinthe particle size is smaller than about 0.05 μm; including a refractoryceramic powder, whereby the composition is a blend; and wherein therefractory ceramic powder is a material selected from the groupconsisting of AlN, BC, BN, Al2O3, ZrO2, and Si.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an embodiment of a process flow diagram in accordance with thepresent inventions.

FIG. 2A is a side perspective view of a single cube structure polymerderived SiC in accordance with the present inventions.

FIG. 2B is a top view of the SiC cubic structure of FIG. 2A.

FIG. 3A is a side perspective view of a tetrahedral structure polymerderived SiC in accordance with the present inventions.

FIG. 3B is a top view of the SiC tetrahedral structure of FIG. 3A.

FIG. 4 is a three-phase diagram chart in accordance with the presentinventions.

FIG. 4A shows an area of embodiments of formulations in accordance withthe present inventions, on the three-phase chart of FIG. 4.

FIG. 4B shows embodiments of transformation taking place duringembodiments of the processes in accordance with the present inventions,on the three-phase chart of FIG. 4.

FIG. 5 is a schematic diagram of an embodiment of a system for makingpolymer derived SiOC and SiC in accordance with the present inventions.

FIG. 6 is a spectrum of a polymer derived SiC in accordance with thepresent inventions.

FIG. 7 is a schematic cross sectional diagram of a vapor depositionapparatus in accordance with the present invention.

FIG. 8 is a schematic cross sectional diagram of a vapor depositionapparatus in accordance with the present invention.

FIG. 9 is a schematic cross sectional diagram of a vapor depositionapparatus in accordance with the present invention.

FIG. 10 a partial pressure cure for SiC, Si₂C, and SiC₂.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In general, the present inventions relate to organosilicon chemistry,polymer derived ceramic materials, and methods; and, in particular tosuch materials and methods for making polysilocarb (SiOC) and SiliconCarbide (SiC) materials having good, high, and exceedingly high purity;and of making SiOC and SiC components, structures and apparatus.Further, and in particular, embodiments of the present inventions relateto the production of high purity SiC, SiC devices, and SiC containingapparatus and equipment, from polysilocarb materials.

Thus, the present inventions provide a new material system and platformhaving many varied formulations, applications and uses, which could notbe obtained with prior silicon based products, and in particular, couldnot have been obtained with prior silicon based products at acceptablecosts, volumes, manufacturing conditions, purity levels, handlingrequirements, and processing conditions, among other things.

Generally, the present inventions are directed toward “polysilocarb”materials, e.g., material containing silicon (Si), oxygen (O) and carbon(C), and materials that have been converted to various forms of SiC fromsuch materials. Polysilocarb materials may also contain other elements.Polysilocarb materials are made from one or more polysilocarb precursorformulation or precursor formulation. The polysilocarb precursorformulation contains one or more functionalized silicon polymers, ormonomers, as well as, potentially other ingredients, such as forexample, inhibitors, catalysts, initiators, modifiers, dopants, andcombinations and variations of these and other materials and additives.Silicon oxycarbide materials, or SiOC compositions and similar terms,unless specifically stated otherwise, refer to polysilocarb materialsthat have been cured into a plastic, or solid material containing Si, Oand C, and polysilocarb materials that have been pyrolized into aceramic material containing Si, O and C.

Typically, and preferably, the polysilocarb precursor formulation isinitially a liquid. This liquid polysilocarb precursor formulation isthen cured to form a solid or semi-sold material, e.g., a plastic. Thepolysilocarb precursor formulation may be processed through an initialcure, to provide a partially cured material, which may also be referredto, for example, as a preform, green material, or green cure (notimplying anything about the material's color). The green material maythen be further cured. Thus, one or more curing steps may be used. Thematerial may be “end cured,” i.e., being cured to that point at whichthe material has the necessary physical strength and other propertiesfor its intended purpose. The amount of curing may be to a final cure(or “hard cure”), i.e., that point at which all, or essentially all, ofthe chemical reaction has stopped (as measured, for example, by theabsence of reactive groups in the material, or the leveling off of thedecrease in reactive groups over time). Thus, the material may be curedto varying degrees, depending upon its intended use and purpose. Forexample, in some situations the end cure and the hard cure may be thesame.

The curing may be done at standard ambient temperature and pressure(“SATP”, 1 atmosphere, 25° C.), at temperatures above or below thattemperature, at pressures above or below that pressure, and over varyingtime periods (both continuous and cycled, e.g., heating followed bycooling and reheating), from less than a minute, to minutes, to hours,to days (or potentially longer), and in air, in liquid, or in apreselected atmosphere, e.g., Argon (Ar) or nitrogen (N₂).

The polysilocarb precursor formulations can be made into non-reinforced,non-filled, composite, reinforced, and filled structures, intermediatesand end products, and combinations and variations of these and othertypes of materials. Further, these structures, intermediates and endproducts can be cured (e.g., green cured, end cured, or hard cured),uncured, pyrolized to a ceramic, and combinations and variations ofthese (e.g., a cured material may be filled with pyrolized beads derivedfrom the same polysilocarb as the cured material).

The precursor formulations may be used to form a “neat” material, (by“neat” material it is meant that all, and essentially all of thestructure is made from the precursor material or unfilled formulation;and thus, there are no fillers or reinforcements). They may be used toform composite materials, e.g., reinforced products. They may be used toform non-reinforced materials, which are materials that are made ofprimarily, essentially, and preferably only from the precursormaterials, for example a pigmented polysiloxane structure having onlyprecursor material and a colorant would be considered non-reinforcedmaterial.

In making the polysilocarb precursor formulation into a structure, part,intermediate, or end product, the polysilocarb formulation can be, forexample, sprayed, flowed, polymer emulsion processed, thermal sprayed,painted, molded, formed, extruded, spun, dropped, injected or otherwisemanipulated into essentially any volumetric shape, including planarshape (which still has a volume, but is more akin to a coating, skin,film, or even a counter top, where the thickness is significantlysmaller, if not orders of magnitude smaller, than the other dimensions),and combinations and variations of these.

The polysilocarb precursor formulations may be used with reinforcingmaterials to form a composite material. Thus, for example, theformulation may be flowed into, impregnated into, absorbed by orotherwise combined with a reinforcing material, such as carbon fibers,glass fiber, woven fabric, non-woven fabric, chopped fibers, metalpowder, metal foams, ceramic foams, fibers, rope, braided structures,ceramic powders, glass powders, carbon powders, graphite powders,ceramic fibers, metal powders, carbide pellets or components, staplefibers, tow, nanostructures of the above, polymer derived ceramics, anyother material that meets the temperature requirements of the processand end product, and combinations and variations of these. Thus, forexample, the reinforcing materials may be any of the high temperatureresistant reinforcing materials currently used, or capable of being usedwith, existing plastics and ceramic composite materials. Additionally,because the polysilocarb precursor formulation may be formulated for alower temperature cure (e.g., SATP) or a cure temperature of for exampleabout 100° F. to about 400° F., the reinforcing material may bepolymers, organic polymers, such as nylons, polypropylene, andpolyethylene, as well as aramid fibers, such as NOMEX or KEVLAR.

The reinforcing material may also be made from, or derived from the samematerial as the formulation that has been formed into a fiber andpyrolized into a ceramic, or it may be made from a different precursorformulation material, which has been formed into a fiber and pyrolizedinto a ceramic. In addition to ceramic fibers derived from the precursorformulation materials that may be used as reinforcing material, otherporous, substantially porous, and non-porous ceramic structures derivedfrom a precursor formulation material may be used.

The polysilocarb precursor formulation may be used to form a filledmaterial. A filled material would be any material having other solid, orsemi-solid, materials added to the polysilocarb precursor formulation.The filler material may be selected to provide certain features to thecured product, the ceramic product or both. These features may relate toor be aesthetic, tactile, thermal, density, radiation, chemical,magnetic, electric, and combinations and variations of these and otherfeatures. These features may be in addition to strength. Thus, thefiller material may not affect the strength of the cured or ceramicmaterial, it may add strength, or could even reduce strength in somesituations.

The filler material could impart, regulate or enhance, for example,electrical resistance, magnetic capabilities, band gap features, p-njunction features, p-type features, n-type features, dopants, electricalconductivity, semiconductor features, anti-static, optical properties(e.g., reflectivity, refractivity and iridescence), chemicalresistivity, corrosion resistance, wear resistance, abrasionsresistance, thermal insulation, UV stability, UV protective, and otherfeatures that may be desirable, necessary, and both, in the end productor material.

Thus, filler materials could include copper lead wires, thermalconductive fillers, electrically conductive fillers, lead, opticalfibers, ceramic colorants, pigments, oxides, dyes, powders, ceramicfines, polymer derived ceramic particles, pore-formers, carbosilanes,silanes, silazanes, silicon carbide, carbosilazanes, siloxane, metalpowders, ceramic powders, metals, metal complexes, carbon, tow, fibers,staple fibers, boron containing materials, milled fibers, glass, glassfiber, fiber glass, and nanostructures (including nanostructures of theforgoing) to name a few. For example, crushed, polymer derived ceramicparticles, e.g., fines or beads, can be added to a polysilocarbformulation and then cured to form a filled cured plastic material,which has significant fire resistant properties as a coating or in adevice or component of a device.

The polysilocarb formulation and products derived or made from thatformulation may have metals and metal complexes. Thus, metals as oxides,carbides or silicides can be introduced into precursor formulations, andthus into a silica matrix in a controlled fashion. Thus, usingorganometallic, metal halide (chloride, bromide, iodide), metal alkoxideand metal amide compounds of transition metals and then copolymerizingin the silica matrix, through incorporation into a precursor formulationis contemplated.

For example, Cyclopentadienyl compounds of the transition metals can beutilized. Cyclopentadienyl compounds of the transition metals can beorganized into two classes: Bis-cyclopentadienyl complexes; andMono-cyclopentadienyl complexes. Cyclopentadienyl complexes can includeC₅H₅, C₅Me₅, C₅H₄Me, CH₅R₅ (where R=Me, Et, Propyl, i-Propyl, butyl,Isobutyl, Sec-butyl). In either of these cases Si can be directly bondedto the Cyclopentadienyl ligand or the Si center can be attached to analkyl chain, which in turn is attached to the Cyclopentadienyl ligand.

Cyclopentadienyl complexes, that can be utilized with precursorformulations and in products, can include: bis-cyclopentadienyl metalcomplexes of first row transition metals (Titanium, Vanadium, Chromium,Iron, Cobalt, Nickel); second row transition metals (Zirconium,Molybdenum, Ruthenium, Rhodium, Palladium); third row transition metals(Hafnium, Tantalum, Tungsten, Iridium, Osmium, Platinum); Lanthanideseries (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho); and Actinide series(Ac, Th, Pa, U, Np).

Monocyclopentadienyl complexes may also be utilized to provide metalfunctionality to precursor formulations and would includemonocyclopentadienyl complexes of: first row transition metals(Titanium, Vanadium, Chromium, Iron, Cobalt, Nickel); second rowtransition metals (Zirconium, Molybdenum, Ruthenium, Rhodium,Palladium); third row transition metals (Hafnium, Tantalum, Tungsten,Iridium, Osmium, Platinum) when preferably stabilized with properligands, (for instance Chloride or Carbonyl).

Alky complexes of metals may also be used to provide metal functionalityto precursor formulations and products. In these alkyl complexes the Sicenter has an alkyl group (ethyl, propyl, butyl, vinyl, propenyl,butenyl) which can bond to transition metal direct through a sigma bond.Further, this would be more common with later transition metals such asPd, Rh, Pt, Ir.

Coordination complexes of metals may also be used to provide metalfunctionality to precursor formulations and products. In thesecoordination complexes the Si center has an unsaturated alkyl group(vinyl, propenyl, butenyl, acetylene, butadienyl) which can bond tocarbonyl complexes or ene complexes of Cr, Mo, W, Mn, Re, Fe, Ru, Os,Co, Rh, Ir, Ni. The Si center may also be attached to a phenyl,substituted phenyl or other aryl compound (pyridine, pyrimidine) and thephenyl or aryl group can displace carbonyls on the metal centers.

Metal alkoxides may also be used to provide metal functionality toprecursor formulations and products. Metal alkoxide compounds can bemixed with the Silicon precursor compounds and then treated with waterto form the oxides at the same time as the polymer, copolymerize. Thiscan also be done with metal halides and metal amides. Preferably, thismay be done using early transition metals along with Aluminum, Galliumand Indium, later transition metals: Fe, Mn, Cu, and alkaline earthmetals: Ca, Sr, Ba, Mg.

Compounds where Si is directly bonded to a metal center which isstabilized by halide or organic groups may also be utilized to providemetal functionality to precursor formulations and products.

Additionally, it should be understood that the metal and metal complexesmay be the continuous phase after pyrolysis, or subsequent heattreatment. Formulations can be specifically designed to react withselected metals to in situ form metal carbides, oxides and other metalcompounds, generally known as cermets (e.g., ceramic metalliccompounds). The formulations can be reacted with selected metals to formin situ compounds such as mullite, alumino silicate, and others. Theamount of metal relative to the amount of silica in the formulation orend product can be from about 0.1 mole % to 99.9 mole %, about 1 mole %or greater, about 10 mole % or greater, and about 20 mole percent orgreater. The forgoing use of metals with the present precursor formulascan be used to control and provide predetermined stoichiometries.

The polysilocarb batch may also be used a binder in compositestructures, such as a binder for metal, ceramic, and inorganic matrices.

Filled materials would include reinforced materials. In many cases,cured, as well as pyrolized polysilocarb filled materials can be viewedas composite materials. Generally, under this view, the polysilocarbwould constitute the bulk or matrix phase, (e.g., a continuous, orsubstantially continuous phase), and the filler would constitute thedispersed (e.g., non-continuous), phase.

It should be noted, however, that by referring to a material as “filled”or “reinforced” it does not imply that the majority (either by weight,volume, or both) of that material is the polysilcocarb. Thus, generally,the ratio (either weight or volume) of polysilocarb to filler materialcould be from about 0.1:99.9 to 99.9:0.1. Smaller amounts of fillermaterial or polysilocarb could also be present or utilized, but wouldmore typically be viewed as an additive or referred to in other manners.Thus, the terms composite, filled material, polysilocarb filledmaterials, reinforced materials, polysilocarb reinforced materials,polysilocarb filled materials, polysilocarb reinforced materials andsimilar such terms should be viewed as non-limiting as to amounts andratios of the material's constitutes, and thus in this context, be giventheir broadest possible meaning.

Depending upon the particular application, product or end use, thefiller can be evenly distributed in the precursor formulation, unevenlydistributed, a predetermined rate of settling, and can have differentamounts in different formulations, which can then be formed into aproduct having a predetermined amounts of filler in predetermined areas,e.g., striated layers having different filler concentration.

As used herein, unless specified otherwise the terms %, weight % andmass % are used interchangeably and refer to the weight of a firstcomponent as a percentage of the weight of the total, e.g., formulation,mixture, material or product. As used herein, unless specified otherwise“volume %” and “% volume” and similar such terms refer to the volume ofa first component as a percentage of the volume of the total, e.g.,formulation, material or product.

At various points during the manufacturing process, the polysilocarbstructures, intermediates and end products, and combinations andvariations of these, may be machined, milled, molded, shaped, drilled orotherwise mechanically processed and shaped.

The precursor formulations are preferably clear or are essentiallycolorless and generally transmissive to light in the visiblewavelengths. They may, depending upon the formulation have a turbid,milky or clouding appearance. They may also have color bodies, pigmentsor colorants, as well as color filler (which can survive pyrolysis, forceramic end products, such as those used in ceramic pottery glazes). Theprecursor may also have a yellow or amber color or tint, without theneed of the addition of a colorant.

The precursor formulations may be packaged, shipped and stored for lateruse in forming products, e.g., structures or parts, or they may be useddirectly in these processes, e.g., continuous process to make a product.Thus, a precursor formulation may be stored in 55 gallon drums, tanktrucks, rail tack cars, onsite storage tanks having the capable ofholding hundreds of gals, and shipping totes holding 1,000 liters, byway of example. Additionally, in manufacturing process the formulationsmay be made and used in a continuous, and semi-continuous processes.

The present formulations, among other things, provide substantialflexibility in designing processes, systems, ceramics, having processingproperties and end product performance features to meet predeterminedand specific performance criteria. Thus, for example the viscosity ofthe precursor formulation may be predetermined by the formulation tomatch a particular morphology of the reinforcing material, the curetemperature of the precursor formulation may be predetermined by theformulation to enable a prepreg to have an extended shelf life. Theviscosity of the of the precursor formulation may be established so thatthe precursor readily flows into the reinforcing material of the prepregwhile at the same time being thick enough to prevent the precursorformulation from draining or running off of the reinforcing material.The formulation of the precursor formulation may also, for example, besuch that the strength of a cured preform is sufficient to allow roughor initial machining of the preform, prior to pyrolysis.

Custom and predetermined control of when chemical reactions occur in thevarious stages of the process from raw material to final end product canprovide for reduced costs, increased process control, increasedreliability, increased efficiency, enhanced product features, increasedpurity, and combinations and variation of these and other benefits. Thesequencing of when chemical reactions take place can be based primarilyupon the processing or making of precursors, and the processing ormaking of precursor formulations; and may also be based upon cure andpyrolysis conditions. Further, the custom and predetermined selection ofthese steps, formulations and conditions, can provide enhanced productand processing features through chemical reactions, moleculararrangements and rearrangements, and microstructure arrangements andrearrangements, that preferably have been predetermined and controlled.

Turning to FIG. 1 there is provided a process flow chart 100 for acollective embodiment having several embodiments of the presentprocesses and systems. Thus, there is a precursor make up segment 101,where the polysilocarb precursor formulations are prepared. There is aforming and distribution segment 102, where the liquid precursorformulation 103 a is prepared for subsequent segments.

There is a curing segment 104, where the liquid precursor 103 a is curedto a cured material 103 b, which is substantially solid, and preferablya solid. There is a pyrolysis segment 105 where the cured material 103 bis converted to a ceramic 103 c, which preferably is SiOC or SiC, andmore preferably high, and very high purity SiOC or SiC. There is apost-processing segment 108, where the ceramic 103 c is furtherprocessed, e.g., washing, pelletizing, extraction, grinding, sieving,etc. The SiOC ceramic 114 can be used in any number (“n” in the figure)of other segments 106, to make intermediate and end products and forvarious applications. Similarly, the post-processed ceramic SiOC 114 pcan be used in any number (“n” in the figure) of other segments 109, tomake intermediate and end products and for various applications. Itbeing understood that the segments 106 and 109 may be the same ordifferent segments. The ceramic SiC 113 can be used in any number ofother segments 107, to make intermediate and end products and forvarious applications. Similarly, the post-processed ceramic SiC 113 pcan be used in a segment 110, e.g., a sintering process. Thepost-processed ceramic SiC 113 p can be used in segment 111, e.g., avapor deposition process to form boules of SiC for segment 112, e.g.,processing into SiC wafers for use in, among other things,semiconductors. The post-process ceramic SiC 113 p can be used in anynumber (“n” in the figure) of other segments 115, to make intermediateand end products and for various applications.

One of the many advantages of the present inventions is that segments106, 107, 109, 110, 111, and 115, generally can be interchangeable.Further, these segments may be processes, methods, applications, anduses that are traditionally for Si. Thus, one of the many advantages ofthe present inventions is the ability to use the SiOC, SiC, andcombinations of the SiOC and SiC, and in particular high purity andultra high purity SiOC, SiC and combinations thereof in, and for, Siintermediate products, Si end products, Si applications and Si uses; andin particular for Si applications where it was previously believed thatSiC was not viable for economic, purity and other rationales. Morepreferably, and one of the many advantages of the present inventions, isthe ability to obtain the requites levels of purity of the SiC to be ofequal or better performance, e.g., features, functions, than Si.Further, one of the many advantages of the present inventions is theability to use the SiOC or the SiC in intermediate products, endproducts and applications and uses, where Si performed or functionedpoorly, or not at all, such as in high temperature sensors and other andnew applications and uses.

In high purity and ultra high purity applications, the precursorpreparation segments 101 and 102, e.g., its equipment and procedures,should be such as to remove, avoid, prevent, and combinations andvariations of these, any contamination (e.g., materials seen asimpurities in the end product) of the starting materials. Thus, in anembodiment the segment should be free from (e.g., contain little,essentially none, and entirely none of) the following materials: B, Na,Al, P, Fe, heavy metals, and halogens, to name a few. Distillation, ionexchange filtration and other types of purification techniques can beuse to remove impurities from starting materials and raw materials.

In segments 105, 106, 107, 108, 109, 110, (and 104 to the extent that itis combined with another segment), the heating equipment, e.g., furnacesthat may be used can be any type of furnace that can reach and maintainthe desired temperatures, e.g., for pyrolysis and conversion to SiC, ofup to about 2,900° C., up to about 2,800° C., above 2,300° C., andpreferably in the range of about 1,200° C. to about 2,800° C. Theheating equipment for the curing stage (e.g., segment 104) in theprocess can be any furnace that can reach the curing temperatures tocure the liquid polymer derived ceramic precursor material, e.g., liquidSiOC formulation, into a solid or semisolid material, e.g., curedmaterial. Thus, one furnace may be used to conduct the entire processfrom liquid polymer derived ceramic to SiC, or two or three differentfurnaces may be used. In an embodiment one furnace is used to cure theliquid precursor to a cured SiOC material, and a second, differentfurnace is used to transform the SiOC material into SiC.

Preferably for high purity and ultra-high purity applications, materialsand uses: such as, SiOC production, SiC production, sintering, pressing,optics formation, boule production, signal crystal growth, crystal layerformation, layer formation, coatings, or wafer production, the heatingequipment, e.g., furnaces, are substantially free from, and morepreferably free from, any materials that are considered impurities inthe end product. For example, the heating equipment, and in particularthe internal components, and all components in fluid communication withthe internal components, can be free from (e.g., contain little,essentially none, and entirely none of) the following materials: B, Na,Al, P, Fe, and heavy metals, to name a few. A cleaning or purging cyclecan be run with the furnaces to remove any impurities or contaminantsbefore processing of the polymer derived ceramic materials. Thus, forexample, vacuum, a high temperature heating cycle, purging with an inertgas such Argon, and combinations and variations of these steps canpreferably be used to make the furnace free from contaminants.

By way of example, these furnaces can include: RF furnaces, Microwavefurnaces, box furnaces, tube furnaces, crystal-growth furnaces, arc meltfurnaces, induction furnaces, kilns, MoSi2 heating element furnaces,gas-fired furnaces, carbon furnaces, vacuum furnaces. Furnaces maycontain spacer materials so as to prevent certain materials to contactone another at high temperature. For example, graphite in contact withalumina at high temperature (>1500° C.) can lead to aluminumcontamination in the final product, and thus spacers may be used tominimize, mitigate or prevent this from occurring. Preferably, furnacecomponents are all constructed from high purity graphite. They may alsobe constructed of, or coated with high purity SiC.

The furnaces, in segments 104, 105, 106, 107, 108, 109, 110 may control,or have equipment and apparatus that control, the environment within thefurnace; and in particular, the environment adjacent to the materialthat is being cured, pyrolized, or converted. Thus, equipment to providefor vacuum conditions, reduced pressure, preselected atmospheres (e.g.Argon), flowing or sweeping gas streams, and combinations and variationsof these may be used. These systems and apparatus should be free from,and constructed to minimize and preferably prevent the introduction ofcontaminates or impurities into the furnace, and in particular into thematerial being processed.

With many polymer derived ceramic materials, and in particular with someSiOC materials, during pyrolysis and conversion, off-gassing from thematerials can take place. In some situations the off-gases produced canbe flammable, can have recoverable materials of value (e.g., Si), andcombinations of these. Thus, and preferably, the furnaces have off-gashandling apparatus, that can mitigate any flammability issues with theoff-gas stream (e.g., an after burner), that can remove and recover anymaterials of value from the gas stream (e.g., scrubbers) andcombinations of these, and other off-gas or gas stream processing andhandling equipment and apparatus.

In the various segments of the process of FIG. 1, the material holdingequipment for holding the liquid precursor formulations during curing,pyrolysis, conversion, or other transformation, can be for exampleAlumina, binder-less h-BN, Graphite, halogen-purified graphite,pyrolitic graphite, SiC, CVD-SiC, polymer-derived SiC, PVT-SiC. Avariety of coatings can also be employed on these materials, includingbut not limited to, TaC, SiC, pyrolitic graphite. The container itselfcan be a crucible, a boat, a machined mold to form any desired geometry(pills, pucks, spheroids, ellipsoids, etc.). It may or may not be fullyenclosed, but may have venting holes to allow for gasses to escape.Preferably, a fitted lid to the vessel is used and the vessel isdesigned to enable venting of gasses during pyrolysis and conversion.Most preferably, inert gas is also purged through the vessel, forexample, at a rate from about 0.5 volume exchanges of the vessel perhour to about 20, from about 5 volume exchanges of the vessel per hourto about 15, and preferably at a rate that does not exceed 10 volumeexchanges of the vessel per hour.

It further being understood that the process flow arrows, e.g., 150, inthe embodiment of FIG. 1 are for the purposes of general illustration,and that: the various segments could be performed in a step wise, orbatch process (included where the segments are at different locations,separated by time, e.g., a few hours, a few days, months or longer, andboth); the various segments could be performed as a continuous process;one or more of the various segments could be combined, e.g., a singlepiece of equipment could perform one of more of the operations ofdifferent segments; and combinations and variations of these.

In embodiments of the segments of FIG. 1, the liquid precursors arecured to a solid SiOC. The solid SiOC is then pyrolized and convertedinto SiC. In one of these embodiments the SiOC may be in a volumetricshape, e.g. a puck, pill, or disc, which is then directly converted intoa friable mass of SiC, without the need for intermediate processingsteps. In one of these embodiments the SiOC is ground into granular SiOCand then converted into granular SiC, which is then formed into avolumetric shape, e.g., a friable mass of SiC. In one of theseembodiments the SiOC is formed into SiC of varying size particles. Theseparticles are then ground down to smaller, and preferably more uniformsizes, or granules, and then these granules are formed, e.g., pressed,into a volumetric shape, or mass of SiC. In these, as well as, otherembodiments when making high purity, and ultra-high purity, SiC it ispreferably to have all components of the system free of substances thatare viewed as impurities in the subsequent uses or process for the SiC;or to have these components shielded, encases or otherwise havingmitigation steps implemented to avoid the introduction of impuritiesinto the process, and the SiC.

In general, and preferably, embodiments of the precursor formulationshave controlled and predetermined amounts, e.g., ratios of O, C and Si.In this manner the starting building bocks for the SiC are in essencepreferably built into the liquid polymer and preferably locked into thecured material. With the building starting blocks being predeterminedthe processing conditions can then be preselected and controlled toobtain the desired end product, e.g., stoichiometric high purity andultra-high purity SiC. The ratios of starting building blocks canfurther be predetermined to provide influence over, or to otherwiseaffect the reactions and rearrangements that are taking place during theprocesses, for example, an initial excess of one component can bepresent to drive the process in a particular direction, e.g., to favorthe creation of CO over SiO. Thus, and further, it may be possible tocontrol and predetermine the type, features, or form, e.g., polytype, ofSiC that is obtained, by predetermining and controlling the ratios ofthese building blocks, any additives and the processing parameters.

For illustration purposes the relationship of the starting buildingblocks, process conditions and end product can, in part, be explained byreference to the three-phase diagram 400 of FIG. 4. Each corner of thediagram 400, represents 100% of a building block, thus corner 401 is100% Carbon, corner 402 is 100% Oxygen, and corner 403 is 100% Silicon.The point 404 on the diagram 400 corresponds to SiC, point 405 on thediagram 400 corresponds to SO₂, and point 406 and 407 on the diagram 400corresponds to CO₂ and CO respectively. Further, the base 410corresponds to the molar % of C, the right side 411 corresponds to themolar % O, and the left side 412 corresponds to the molar % Si. (Bymolar % X, it is meant the moles of X to the total moles of O, C, andSi, as a percentage.) Thus, the molar ratios of starting materials in aprecursor formulation batch can generally, and without limitation, befrom about 30% to about 85% Carbon, from about 5% to about 40% Oxygen,and from about 5% to about 35% Silicon. Preferably, in embodiments ofthe SiOC starting materials and cured materials, the molar ratio of C,Si and O, can be within about the cross-hatched area 430 of FIG. 4A.Although, ratios outside of that area are contemplated.

Generally, the process for obtaining SiC goes from a liquid precursorformulation to a cured material, to a pyrolized SiOC material, which isconverted to a SiC material (alpha, beta, or both). During theseprocesses—curing, pyrolizing and converting, some of the variousbuilding blocks are lost, typically C and O. Si may also be lost, butpreferably the process and the precursor are such that Si loss isminimal to none. For example, excess C, built into the precursor or froman external source, e.g., in the oven, will drive the formation of COover SiO resulting in less loss of Si. The greater degree ofcross-linking that takes place in the cured material, the lower the Silosses during pyrolizing and converting, and thus, the greater the yieldof SiC.

Turning again to the three-phase diagram 400, in FIG. 4B there is shownthe general shift in ratio that can be anticipated with variousprocesses. It being understood that the various arrows are only generaldirections of movements for examples of processing activities; and theirslopes may vary, depending upon the actual conditions, for example ifhydrocarbons and CO₂ are both being given off. Thus, the removal ofvolatile hydrocarbons will shift the ratio generally in the direction ofarrow 450. During curing or storage thereafter the material may pick upsome water from the atmosphere, which ratio shift is shown by arrow 451(combined water pick up and volatile loss). The ratio shift from thegeneration of SiO is shown by arrow 454. The ratio shift from thegeneration of CO is shown by arrow 453, and the ratio shift from thegeneration of CO₂ is shown by arrow 452. In being understood that theultimate goal of the process is to get the ratio of materials from theirstarting ratio to the base line 410, and in some situations, mostpreferably to stoichiometric SiC, point 404.

The ability to start with a liquid material, e.g., the precursor batch,having essentially all of the building blocks, e.g., Si and C, needed tomake SiC provides a significant advantage in controlling impurities,contamination, and in making high purity SiOC, which in turn can beconverted to high purity SiC, or which can be made directly in a singlecombined process or step. Thus, embodiments of the present inventionsprovide for the formation of SiOC that is at least about 99.9%(3-nines), at least about 99.99% (4-nines), at least about 99.999%(5-nines), and least about 99.9999% (6-nines) and at least about99.99999% (7-nines) or greater purity. Similarly, embodiments of thepresent inventions provide for the formation of SiC that is at leastabout 99.9% (3-nines), at least about 99.99% (4-nines), at least about99.999% (5-nines), and least about 99.9999% (6-nines) and at least about99.99999% (7-nines) or greater purity. These purity values are basedupon the amount of SiOC, or SiC, as the case may be, verse all materialsthat are present or contained within a given sample of SiOC or SiCproduct.

Embodiments of the present polysilocarb derived SiC and processes,reduce the cost of providing high purity and ultra high purity SiC,while also increasing the purity obtained, e.g., lower cost high puritySiC materials. Thus, among other things, embodiments of the polysilocarbSiC materials and articles have reduced costs and enhanced features,when compared to prior SiC, SiOC and Si materials and products Thus,among other things, embodiments of the polysilocarb SiC materials andarticles can replace SiC as well as Si materials and products in manyapplications, and have to ability to provide for new, additional andenhanced applications that were not obtainable with SiC and Si materialsand products for technical, economic, and both, reasons.

Embodiments of polymer derived SiC wafers include, among others, about2-inch diameter wafers and smaller, about 3-inch diameter wafers, about4-inch diameter wafers, about 5-inch diameter wafers, about 6-inchdiameter wafers, about 7-inch diameter wafers, about 12-inch diameterwafers and potentially larger, wafers having diameters from about 2inches to about 8 inches, wafers having diameters from about 4 inches toabout 6 inches, square shaped, round shaped, and other shapes, surfacearea per side of about 1 square inch, about 4 square inches, about 10square inches and larger and smaller, a thickness of about 100 μm, athickness of about 200 μm, a thickness of about 300 μm, a thickness ofabout 500 μm, a thickness of about 700 μm, a thickness from about 50/mto about 800 μm, a thickness from about 100/m to about 700 μm, athickness from about 100/m to about 400 μm, and larger and smallerthickness, and combinations and variations of these.

In embodiments of the present inventions the high purity SiC has low,very and low and below detection limits, amounts of materials that causesignificant problems, or are viewed as impurities, in the laterprocessing and manufacture of items, for example, boules, wafers,electronic components, optical components and other SiC basedintermediate and end products.

Thus, polymer derived high purity SiC, and in particular polysilocarbderived high purity SiOC, as well as, the high purity SiC that the SiOCis converted into, has a purity of at least about 99.9%, at least about99.99%, at least about 99.999%, and least about 99.9999% and at leastabout 99.99999% or greater. Further, it is noted that embodiments of thepresent invention include polymer derived SiC, and SiOC, of any puritylevel, including lower levels of purity, such as 99.0%, 95%, 90% andlower. It is believe that these lower, e.g., non-high, purityembodiments have, and will find, substantial uses and applications.Similarly, it is believed that embodiments of the high purity SiC willfind applications, uses, and provide new and surprising benefits toapplications that prior to the present inventions were restricted to Sior materials other than SiC.

Embodiments of the present inventions include the use of high purity SiCin making wafers for applications in electronics and semiconductorapplications. In both the vapor deposition apparatus and processes tocreate the boules and wafers for later use, high purity SiC is required.In particular, as set forth in Table 3, embodiments of high puritypolymer derived SiOC and SiC can preferably have low levels of one, morethan one, and all elements in Table 3, which in certain vapor depositionapparatus, electronics applications, and semiconductor applications areconsidered to be impurities. Thus, embodiments of polysilocarb derivedSiC can be free of impurities, substantially free of impurities, andcontain some but have no more than the amounts, and combinations ofamounts, set out in Table 3.

TABLE 3 less than less than less than less than less than Element ppmppm ppm ppm ppm Al 1,000 100 10 1 0.1 Fe 1,000 100 10 1 0.1 B 1,000 10010 1 0.1 P 1,000 100 10 1 0.1 Pt 1,000 100 10 1 0.1 Ca 1,000 100 10 10.1 Mg 1,000 100 10 1 0.1 Li 1,000 100 10 1 0.1 Na 1,000 100 10 1 0.1 Ni1,000 100 10 1 0.1 V 1,000 100 10 1 0.1 Ti 1,000 100 10 1 0.1 Ce 1,000100 10 1 0.1 Cr 1,000 100 10 1 0.1 S 1,000 100 10 1 0.1 As 1,000 100 101 0.1 Total of one or 3,000 500 50 10 1 more of the above

In an embodiment, Pr may also be considered an impurity in someapplications and if so consider the limits and amounts of table 3 may beapplicable to Pr.

Unless specified otherwise, as used herein, when reference is made topurity levels, high purity, % purity, % impurities, and similar suchterms, excess carbon, i.e., beyond stoichiometric SiC, is not included,referenced to, considered, or used in the calculations orcharacterization of the material. In some applications excess carbon mayhave little to no effect on the application or product, and thus, wouldnot be considered an impurity. In other applications excess carbon maybe beneficial, e.g., carbon can act as a sintering aid; excess carboncan be used to address and compensate for irregularities in vapordeposition apparatus and processes.

In applications where nitrogen is viewed as a contaminate, embodimentsof polysilocarb derived SiC and SiOC can have less than about 1000 ppm,less than about 100 ppm, less than about 10 ppm, less than about 1 ppmand less than about 0.1 ppm nitrogen, and lower.

In an embodiment of the polysilocarb derived SiC it is essentially freefrom, and free from the presence of Oxygen, in any form, either bound toSi or C or as an oxide layer. Thus, embodiments of polysilocarb derivedSiC can have less than about 1000 ppm, less than about 100 ppm, lessthan about 10 ppm, less than about 1 ppm, and less than about 0.1 ppmoxygen, and lower. The polysilocarb derived SiC has the ability toresist, and does not form an oxide layer when exposed to air understandard temperatures and pressures. The absence of an oxide layer,i.e., oxide layer free SiC, under when stored under ambient conditionsprovides advantages in later manufacturing processes, where oxide layerscan be viewed as an impurity, or otherwise a detriment to themanufacturing process.

Embodiments of polysilocarb derived SiC are highly versatile materials.They can have several forms, e.g., amorphous, crystalline having manydifferent polytypes, and forming single (or mono-) and polycrystallinestructures. One, more than one, and combinations of these various forms,many be in a single batch, volumetric shape, or sample of polysilocarbderived SiC. Thus, the present polysilocarb derived SiC materials findsapplications in among other things, abrasives, friction members, optics,ballistic and impact resistant materials, insulation, and electronics.

Polysilocarb derived SiC powder, fines, pellets, or other smaller sizedand shaped forms, can be joined together by way of a sintering operationto form component parts and structures.

The joining together, e.g., pressing, sintering, ready-to-press, ofembodiments of the present polymer derived SiC can be done in anyconventional process, and can be done with the use of sintering aids andother additives that are presently used in conventional processes.Embodiments of the present ultra pure polymer derived SiC provideunique, and believed to be never before present in an SiC, abilities tohave their particles joined together without the need for any sinteringaids, or processing additives. Thus, embodiments of the present ultrapure SiC are self-sintering, being that they do not require the presenceof any sintering aids or additives in order to be joined or otherwiseformed, e.g., sintered or pressed, into a solid and preferablymonolithic solid shape. The self-sintered ultra pure SiC shapes can besignificantly stronger than a corresponding shape that was made with theuse of sintering aids. Thus, the self-sintered SiC shape can be 2×, 3×,4× or more stronger than a similar SiC shape that used sintering aids.It being theorized that the sintering aids are forming bonds orjunctures between the SiC particles and that these sintering aidjunctures are substantially weaker than the SiC-to-SiC junctures, e.g.,direct junctures, in the self-sintered shape.

Embodiments of the present polymer derived SiC, and in particular ultrapure SiC, through vapor deposition processes, crystalline growthprocesses, joining processes and other processes, can find applicationsand utilizations in among other things, broad band amplifiers, militarycommunications, radar, telecom, data link and tactical data links,satcom and point-to-point radio power electronics, LED, lasers, lightingand sensors. Additionally, these embodiments can find applications anduses in transistors, such High-electron-mobility transistors (HEMT),including HEMT-based monolithic microwave integrated circuit (MMIC).These transistors can employ a distributed (traveling-wave) amplifierdesign approach, and with SiC's greater band gap, enabling extremelywide bandwidths to be achieved in a small footprint. Thus, embodimentsof the present inventions would include these devices and articles thatare made from or otherwise based upon polymer derived SiC.

Embodiments of the present polymer derived SiC, and in particular ultrapure SiC, through vapor deposition processes, crystalline growthprocesses, joining processes and other processes, can also findapplications and utilizations in among other things, brake rotors andassemblies, brake disks and pads, to make gemstones and semipreciousstones, jewelry, moissanite, and cutting and abrasive applications.Thus, embodiments of the present inventions would include these devicesand articles that are made from or otherwise based upon polymer derivedSiC.

Embodiments of the present polymer derived SiC, and in particular ultrapure SiC, can be combined with other ceramic power formulations toprovide enhanced benefits, reduced costs and both to processes that usesthese other ceramic powers. For example BN/SiC/ZrO2 composites, andblends with other refractory/engineering ceramic powders, e.g., AlN, BC,BN, Al2O3, ZrO2, C, SiC, WC, and SiN, to name a few are contemplated.Thus, embodiments of the present inventions would include these devicesand articles that are made from or otherwise based upon polymer derivedSiC. They may also be used in metal alloying applications, for exampleto make cermets, or other metallurgy blend and allows. For example theycan be so combined to Ti, Fe, Ni and Co, to name a few. Thus, forexample, they can form polymer derived SiC—Ti alloys, polymer derivedSiC-ferrous alloys, polymer derived SiC—Ni alloys, and polymer derivedSiC—Co alloys.

Embodiments of the present polymer derived SiC ceramic powerformulations can be utilized in, for example, as a component of, or inthe construction of: kiln furniture, furnace tubes, furnace belt links,furnace rollers, nozzles, bearings, corrosion resistant seals,crucibles, refractories, thermal protection systems, RAM-Jet/SCRAM-Jetor anything that flies above Mach 3, rockets, space shuttles, rocketnose-cones and leading edge impact protection systems, SiC/SiCreinforced composites, SiC/C reinforced composites, DC magnetronsputtering targets, thermocouple sheathing, pump seals, and valvesleeves.

Embodiments of the present polymer derived SiC, SiOC and in particularultra pure SiC and SiOC, through vapor deposition processes, crystallinegrowth processes, joining processes and other processes can findapplication and utilization in multi-layer structures, such as, forexample a layer on a substrate. This layer can be crystalline,monocrystalline, polycrystalline, or amorphous. There can be structuresthat have many varied layers, e.g., substrate layer, tie layer, SiClayer, SiOC layer, and other substances. In an embodiment sapphire canbe used as a substrate for an epitaxial SiC layer. GaN can also be anacceptable substrate. A tie layer can be used to moderate the latticemismatch between dissimilar crystalline lattice parameters. Thus, forexample where SiOC is used as a substrate it can have a tie layer tosupport SiC, or GaN layer growth on it.

In an embodiment of this process, high purity, polymer derived SiC, andpreferably very small sized, e.g., less than about 100 μm, less thanabout 10 μm, having a purity of at about 99.999%, preferably about99.9999% and more preferably about 99.99999% can be sintered intooptical components. These optical components can be transmissive toselected wavelengths, e.g., 360-800 nm. They can have indexes ofrefraction of about 2.65 in the visible spectrum. They can have good,and high optical properties, being free of aberrations, occlusions, andother optical defects. They posses the toughness (e.g., chemicalresistance, abrasion resistance, temperature resistance, hardness, ofSiC). Thus, for example, then can provide significant improvements tothe windows, or clear members, e.g., screens, on cell phones, tablets,touch screens and the like. They may be used for the bodies of thesedevices as well. These polymer derived SiC windows can be particularlyadvantageous in demanding applications, where for example, there areharsh environmental or use conditions present. They can be used in manyoptical applications, including: the generation of light, e.g., lasers,laser diodes, or other light sources; the shaping and transmitting oflight, e.g., optical fibers, windows, prisms, lens, optics, mirrors, andinternal reflectance elements (e.g., blocks, prisms that rely uponinternal reflection to direct the light).

In addition to UV, visible and IR light, the SiC optical components canfind applications in over wavelengths of electromagnetic radiation, suchas microwave, millimeter wave, x-ray, and high energy beams.

Embodiments of polysilocarb derived SiC, in particular high purity SiC,have many unique properties that, among other things, make themadvantageous and desirable for use in the electronics, solar, and powertransmission industries and applications. They can function as asemiconductor material that is very stable, and suitable for severaldemanding applications, including high power, high-frequency,high-temperature, and corrosive environments and uses. Polymer derivedSiC is a very hard material with a Young's modulus of 424 GPa. It isessentially chemically inert, and will not react with any materials atroom temperature.

Further, prior to the present inventions, it was believe that it wasessentially impossible, from all practical standpoints, to diffuseanything into silicon carbide, thus to the extent that dopants arerequired to be added to the material, they can be added by way of theprecursor and thus be present in a controlled manner and amount forgrowth into a boule, or other structure. Embodiments of precursorformulations may have dopant, or complexes that carry and bind thedopant into the ceramic and then the converted SiC, so that upon vapordeposition process the dopant is available and in a usable form.

Additionally, dopants or other additives to provide custom orpredetermined properties to wafers, layers and structures that are madefrom embodiments of the polymer derived SiC and SiOC can be used with,as a part of, or in conjunction with the present polymer derivedmaterials. In these embodiments, such property enhancing additives wouldnot be considered impurities, as they are intended to be in, necessaryto have in, the end product. The property enhancing additives can beincorporated into the liquid precursor materials. Depending on thenature of the property enhancing additive, it may be a part of theprecursor back done, it may be complexed, or part of a complex, toincorporate it into the liquid precursors, or it can be present in otherforms that will enable it to survive (e.g., be in a form that lets itfunction as intended in the final material). The property enhancingadditive can also be added as a coating to the SiC or SiOC powderedmaterial, can be added as a vapor or gas during processing, or can be inpowder form and mixed with the polymer derived SiC or SiOC particles, toname a few. Further, the form and manner in which the property enhancingadditive is present, should preferably be such that it has minimal, andmore preferably, no adverse effect on processing conditions, processingtime, and quality of the end products. Thus, a polysilocarb derived SiChaving greater than 5-nines purity, greater than 6-nines purity andgreater than 7-nines purity can have amounts of a property enhancingadditive present. These amounts can be from about 0.01% to about 50%,about 0.1% to about 5%, about 1% to about 10%, less than 25%, less than20%, less than 10% and less than 1%, as well as greater and smalleramounts depending upon the additive and the predetermined properties itis intended to impart.

Silicon carbide does not generally have a liquid phase, instead itsublimes, under vacuum, at temperatures above about 1,800° C. Turning toFIG. 10 there is provided a chart of a partial pressure curve for SiC.Typically, in industrial and commercial applications conditions areestablished so that the sublimation takes place at temperatures of about2,500° C. and above. When Silicon carbide sublimes it typically forms avapor consisting of Si, SiC, and SiC₂. Generally, it was believed thattemperature determined the ratio of these different components in theSilicon carbide vapor. The present inventions, however, among otherthings, provide the capability to preselect and control the ratio ofthese components of a SiC vapor, for example by controlling the amountof excess carbon present in the polysilocarb derived SiC. Further, byvarying, in a controlled manner, the porosity of the polysilocarbderived SiC, the amount of excess carbon present, and both (when used asa starting material in the vapor deposition process), for example, byhaving layers of SiC material having different predetermined amounts ofexcess carbon present, the make up of the Si C vapors can be varied in acontrolled manner, and varied in a control manner over time.

Polysilocarb derived SiC, and the SiC boules, wafers and otherstructures that are made from the polysicocarb derived SiC, exhibitpolymorphism, and generally a one dimensional polymorphism referred toas polytypism. Thus, polysilocarb derived SiC can be present in many,theoretically infinite, different polytypes. As used herein, unlessexpressly provided otherwise, the term polytypism, polytypes and similarsuch terms should be given their broadest possible meaning, and wouldinclude the various different frames, structures, or arrangements bywhich silicon carbide tetrahedrons (SiC₄) are configured. Generally,these polytypes fall into two categories—alpha (α) and beta (β). FIGS.2A and 2B, and 3A and 3B show the side and top view respectively of asingle cubic and tetrahedral polymer derived SiC structure. Thus, inFIGS. 2A and B there are shown the single cubic arrangement of SiC, withSi being open circles, e.g., 200 and C being closed circles, e.g., 201.In FIGS. 3A and B there are shown the single tetrahedral arrangement ofSiC, with Si being open circles, e.g., 300 and C being closed circles,e.g., 301.

Embodiments of the alpha category of polysilocarb derived SiC typicallycontains hexagonal (H), rhombohedral (R), trigonal (T) structures andmay contain combinations of these. The beta category typically containsa cubic (C) or zincblende structure. Thus, for example, polytypes ofpolysilocarb derived silicon carbide would include: 3C—SiC (β-SiC or β3C—SiC), which has a stacking sequence of ABCABC . . . ; 2H—SiC, whichhas a stacking sequence of ABAB . . . ; 4H—SiC, which has a stackingsequence of ABCBABCB . . . ; and 6H—SiC (a common form of alpha siliconcarbide, a 6H—SiC), which has a stacking sequence of ABCACBABCACB . . .. Examples, of other forms of alpha silicon carbide would include 8H,10H, 16H, 18H, 19H, 15R, 21R, 24H, 33R, 39R, 27R, 48H, and 51R.

Embodiments of polysilocarb derived SiC may be polycrystalline or single(mono-) crystalline. Generally, in polycrystalline materials there arepresent grain boundaries as the interface between two grains, orcrystallites of the materials. These grain boundaries can be between thesame polytype having different orientations, or between differentpolytypes, having the same or different orientations, and combinationsand variations of these. Mono-crystalline structures are made up of asingle polytype and have essentially no grain boundaries.

Embodiments of the present inventions provide the ability to meet thedemand for high purity silicon carbide, and in particular high puritysingle crystalline carbide materials for use in end products, such as asemiconductors. Thus, for these end products, and uses, which requirehigh purity materials, it is desirable to have a low cost siliconcarbide raw material that has a purity of at least about 99.9%, at leastabout 99.99%, at least about 99.999%, and least about 99.9999% and atleast about 99.99999% or greater.

High purity single crystalline silicon carbide material has manydesirable features and characteristics. For example, it is very hardhaving a Young's modulus of 424 GPa. Polycrystalline silicon carbide mayalso have very high hardness, depending upon its grain structure andother factors.

Embodiments of the present polysilocarb derived SiC would include theability to provide larger diameter or cross section (e.g., about 5inches, greater than 5 inches, about 6 inches, greater than 7 inches,about 8 inches, greater than 8 inches, greater than 9 inches, about 12inches, and greater) seed crystals, boules and other structures. Suchlarger diameter or cross section structures can preferably have a purityof at least about 99.9%, at least about 99.99%, at least about 99.999%,and least about 99.9999% and at least about 99.99999% or greater.

Embodiments of the present inventions include articles, e.g.,semiconductors, of silicon carbide having a band gap that varies bypolytype between 2.39 eV for (beta SiC) 3C—SiC to 3.33 eV for 2H—SiC.4H—SiC has a band gap of 3.265 eV. Alpha silicon carbide (6H—SiC) has aband gap of 3.023 eV. These band gaps are larger than for Si, which hasa band gap of 1.11 eV. The high band gap allows silicon carbidematerials to work in sensors, e.g., a gas sensor, that are operated inhigh temperature, e.g., up to about 1,000° C., environments. Forexample, a silicon carbide based gas sensor can have response times ofonly a few milliseconds while operating in temperatures of about 1,000°C.

Embodiments of materials made from polymer derived SiC, SiOC, and inparticular high purity polymer derived SiC and SiOC, can be utilized inpower devices and power device applications. For power deviceapplications, the breakdown electric field strength E_(max) can be animportant property. This property quantizes how high the largest fieldin the material may be before material breakdown occurs (e.g.,catastrophic breakdown). The E_(max) is dependent upon doping levels,but in general for a SiC material and a Si material having the samedoping levels the SiC E_(max) can be on the order of 4 to 10 timesgreater. E_(max) and relative E_(max) can also be viewed from theperspective of the relative strengths of a device constructed to havethe same blocking voltage. Thus, an Si device constructed for a blockingvoltage of I kV would have a critical field strength of about 0.2 MV/cm,and a similar SiC device would have a critical field strength of about2.49 MV/cm.

Embodiments of materials made from polymer derived SiC, SiOC, and inparticular high purity polymer derived SiC and SiOC, can be utilized inhigh frequency devices and high frequency applications. Saturation driftvelocity can be an important property for high frequency devices.Silicon carbide has a saturation drift velocity of 2×10⁷ cm/sec², whilea similar silicon's saturation drift velocity is about half of that.High saturation drift velocities are advantageous, if not necessary, forhigh-gain solid state devices. Thus, with embodiments of the presentinventions providing high purity, low cost (e.g., cost effective)silicon carbide, it now can become a preferred choice from a materialsperspective for such devices. However, it is believed that it was achoice that generally the art would not make, prior to the presentinventions, because of the costs associated with utilizing siliconcarbide; and the difficulty, if not impossibility in obtaining theneeded purity.

Embodiments of materials made from polymer derived SiC, SiOC, and inparticular high purity polymer derived SiC and SiOC, can be utilized inhigh thermal conductivity applications. The thermal conductivity ofsilicon carbide is higher than that of copper at room temperature, andit is believe may be superior to most if not all metals. For example thethermal conductivity of silver is 4.18 W/(cm-K), and of copper is 4.0W/(cm-K) at room temperature. High purity silicon carbide can havethermal conductivity of greater than about 4.0 W/(cm-K), greater thanabout 4.5 W/(cm-K), about 4.9 W/(cm-K), and greater at room temperature.

Embodiments of the present inventions, and the advances in SiCprocessing and materials provided by the present inventions, can replacesilicon materials, in many, the majority, if not essentially allelectronics and other applications; as well as additional and new,applications and uses beyond conventional silicon based semiconductorand electrons applications.

Embodiments of polysilocarb derived high purity SiC, e.g., having apurity of at least about 99.9%, at least about 99.99%, at least about99.999%, and least about 99.9999% and at least about 99.99999% orgreater, can have many different polytypes. The polysilocarb derivedhigh purity SiC and SiOC may be present as alpha (α), beta (β) andcombinations and variations of these. Embodiments of the alpha categoryof polysilocarb derived high purity SiC typically contains hexagonal(H), rhombohedral (R), trigonal (T) structures and may containcombinations of these. The beta category of polysilocarb derived highpurity SiC typically contains a cubic (C) or zincblende structure. Thus,for example, polytypes of polysilocarb derived high purity siliconcarbide would include: 3C—SiC (β-SiC or β 3C—SiC); 2H—SiC; 4H—SiC; and6H—SiC (a common form of alpha silicon carbide, a 6H—SiC), which has astacking sequence of ABCACBABCACB . . . . Examples, of other forms ofalpha silicon carbide would include 8H, 10H, 16H, 18H, 19H, 15R, 21R,24H, 33R, 39R, 27R, 48H, and 51R. Embodiments of polysilocarb-derivedhigh purity SiC can be polycrystalline or single (mono-) crystalline.High purity SiOC, and SiOC derived SiC may be in an amorphous form.

Embodiments of the present inventions have the ability to provide, andare, high purity SiOC and SiC in the form of volumetric structures,e.g., pucks, briquettes, bricks, blocks, tablets, pills, plates, discs,squares, balls, rods, random shapes, etc. These volumetric shapes have awide range of sizes, generally from about 1/16 in³ to about 1 ft³,although larger and smaller volumes are contemplated. Embodiments of thevolumetric structures can be very soft, and crumbly, or friable,preferably having the ability to fall apart with average hand pressure.Thus, these friable SiC volumetric structures can have: an elasticmodulus of less than about 200 GPa, less than about 150 GPa, less thanabout 75 GPa, and less than about 10 GPa and smaller; a hardness of lessthan about 1,400 Kg/mm² less than about 800 Kg/mm², less than about 400Kg/mm², less than about 100 Kg/mm² and smaller; and, compressivestrength of less than about 1,850 MPa, of less than about 1,000 MPa ofless than about 750 MPa, of less than about 200 MPa, of less than about50 MPa, and smaller. Thus, these friable SiC volumetric shapes aresubstantially weaker than their underlying SiC material that makes uptheir structure, and which has reported values of elastic modulus ofabout 410 GPa, hardness of about 2,800 Kg/mm² and compressive strengthof about 3,900 MPa. The actual density of the SiC, measured by HeliumPycnometry, is from about 3.0 to 3.5 g/cc, or about 3.1 to 3.4 g/cc, orabout 3.2 to 3.3 g/cc. The apparent density, or specific gravity, forthe friable volumetric shapes of SiC, e.g., pellets, pills, etc., may besignificantly lower.

The mass of SiC (e.g., volumetric shape of the granular SiC particles,friable mass) preferably, and typically, has an apparent density that isconsiderably lower, than its actual density, e.g., actual density of anSiC granule should be about 3.1 g/cc to 3.3 g/cc. In general, andtypically, the apparent and actual density of the granular SiC that isobtained from crushing the friable mass are essentially identical. Theapparent density for the friable mass (e.g. a puck, pellet, disk orplate) can be less than about 3 g/cc, less than about 2 g/cc. less thanabout 1 g/cc and lower, and can be from about 0.5 g/cc to about 1.5g/cc, about 0.4 g/cc to about 2 g/cc. The bulk density for particles ofthe SiC can be less than about 3.0 g/cc, less than about 2.0 g/cc, lessthan about 1 g/cc, and from about 0.1 g/cc to about 2 g/cc, 0.5 g/cc toabout 1.5 g/cc. Greater and lower apparent densities and bulk densitiesare also contemplated. Moreover, specific, i.e., predetermined andprecise, apparent densities for a friable mass of polymer derived SiCcan be provided to match, and preferably enhance and more preferableoptimize, later manufacturing processes. For example, in CVD wafermaking, the friable mass of SiC granules can have an apparent densitythat is specifically designed and tailored to match a specific CVDapparatus. In this manner, each CVD apparatus in a facility can havecustom feed stock, which enables each apparatus' performance to beoptimized by the use of the feed stock (e.g., the friable mass of SiC)having a predetermined and precise apparent density.

The friable SiC volumetric shapes can thus be easily and quickly brokendown into much smaller particles of SiC, having the typical strengthcharacteristics of SiC. The smaller particles can be less than about 10mm in diameter, less than about 1 mm in diameter, less than about 0.01mm in diameter, less than about 100 μm (microns) in diameter, less thanabout 10 μm in diameter, and less than about 1 μm, less than about 500nm (nanometers), to less than about 100 nm it being understood thatsmaller and larger sizes are contemplated.

Thus, embodiments of the present invention provide for the formation ofa friable mass or volumetric shape of SiC, from a SiOC precursor, andfrom this friable mass of SiC obtain granular SiC. The granular SiChaving significantly greater strength than the bulk properties of thefriable mass of SiC. For example, the granular SiC can have an elasticmodulus that is about 2× greater than the mass of SiC, about 3× greaterthan the mass of SiC, about 4× greater than the mass of SiC, andgreater; the granular SiC can have a hardness that is about 2× greaterthan the mass of SiC, about 3× greater than the mass of SiC, about 4×greater than the mass of SiC, and greater; the granular SiC can have ancompressive strength that is about 2× greater than the mass of SiC,about 3× greater than the mass of SiC, about 4× greater than the mass ofSiC, and greater; and combinations and variation of these increasedstrength related features.

The friable mass of SiC that is obtained from for example the process ofthe embodiment of FIG. 1 (e.g., 103 c of segment 108) can be reduced togranular SiC with crushing equipment such as a ball mill, an attritionmill, a rotor stator mill, a hammer mill, a jet-mill, a roller mill, abead mill, a media mill, a grinder, a homogenizer, a two-plate mill, adough mixer, and other types of grinding, milling and processingapparatus.

The friable mass of SiC has an inherent porosity to it. This porosity ispreferably open hole, or substantially open hole porosity. In thismanner, the friable mass typically provides substantially greateravailable surface area than granular SiC, because the granules arepacked against one another. Thus, for example, if a friable discs of SiCwere used in a vapor deposition process to make SiC boules (forsubsequent conversion into SiC wafers), these friable SiC discs wouldprovide substantially greater surface area from which to create SiCvapor, and substantially greater paths for movement of the SiC vapor,than could typically be obtained from using granular SiC in such aprocess. It is theorized that the increase surface area and theincreased pathways, provides the ability to increase the rate of growthof the SiC boule, the quality of the SiC boule (and thus the subsequentwafers) and both of these. The friable SiC discs, e.g., the mass of SiC,may be easier to handle, measure, and use than the granular SiCmaterial.

The friable mass of SiC preferably, and typically, has an apparentdensity that is considerably lower, than its actual density, e.g.,actual density should be about 3.2 g/cc. In generally, the granular SiC,which is obtained from crushing the friable mass, has an apparent andactual density that are essentially identical, e.g., about 3.1 to 3.3g/cc.

The force required to break up the friable mass of SiC to a granularform is minimal, compared to the force that was need with conventionalmethods of making SiC (e.g., by carbothermal reduction of silica,Acheson type or based). The conventional methods, typically produce abatch of SiC in a monolith, having the strength of SiC, and whichtypically must be granulized, e.g., ground, cut, shaved, or milled, downto useful sizes. Thus, embodiments of the present inventions avoid theneed for such heavy or robust grinding equipment to granulize themonolith of SiC. They further avoid the high cost of power, e.g.,electricity, to operate such grinding equipment. They also greatlyreduce the time need to granulize the SiC. It could take upwards ofweek(s), using this heaving grinding equipment, to granulize themonolith SiC to a useful size. While, an embodiment of the friable massof SiC of the present inventions can be granulized in only a few hours,an hour, less than an hour, less than 30 minutes, a few minutes, andless. This grinding process for example can be, for example, postprocessing segment 108 of the embodiment of FIG. 1.

The features of the high purity polysicocarb SiC provide severaladvantages and benefits for use in, e.g., as the Si and C source orstarting material, vapor deposition processes, systems and apparatus,among other techniques for growing or creating a SiC mass, structure,article or volumetric shape. These features include: the ability to havehigh purity levels, a high purity levels, the ability to controlparticle size distribution (shape, size and both); predeterminedparticle size distribution; the ability to have volumetric shapes;predetermined volumetric shapes (e.g., pucks, pills, discs, etc.); theability to have porosity and control porosity; predetermined porosity;the ability to control the amount of carbon; predetermined carbonamounts (both excess, i.e., greater than stoichiometric, starved, i.e.,less than stoichiometric and stoichiometric); and combinations andvariations of these and other properties. While additional advantagesfor the present inventions may be seen, presently and by way of example,these advantages in vapor deposition processes would include shorteningthe time to grow the boule or other structure, longer run times beforecleaning, the ability to optimize an apparatus, the ability to growlarger diameter boules or other structures, the ability to increasequality, the ability to reduce problematic areas, problematic regions orproblematic occurrences (e.g., pipes, occlusions, imperfections) fromthe boule or other structure, reduced costs, greater control over theprocess, and combinations and variations of these.

It should be understood that the use of headings in this specificationis for the purpose of clarity, and is not limiting in any way. Thus, theprocesses and disclosures described under a heading should be read incontext with the entirely of this specification, including the variousexamples. The use of headings in this specification should not limit thescope of protection afford the present inventions.

General Processes for Obtaining a Polysilocarb Precursor

Typically polymer derived ceramic precursor formulations, and inparticular polysilocarb precursor formulations can generally be made bythree types of processes, although other processes, and variations andcombinations of these processes may be utilized. These processesgenerally involve combining precursors to form a precursor formulation.One type of process generally involves the mixing together of precursormaterials in preferably a solvent free process with essentially nochemical reactions taking place, e.g., “the mixing process.” The othertype of process generally involves chemical reactions, e.g., “thereaction type process,” to form specific, e.g., custom, precursorformulations, which could be monomers, dimers, trimers and polymers. Athird type of process has a chemical reaction of two or more componentsin a solvent free environment, e.g., “the reaction blending typeprocess.” Generally, in the mixing process essentially all, andpreferably all, of the chemical reactions take place during subsequentprocessing, such as during curing, pyrolysis and both.

It should be understood that these terms—reaction type process, reactionblending type process, and the mixing type process—are used forconvenience and as a short hand reference. These terms are not, andshould not be viewed as, limiting. For example, the reaction process canbe used to create a precursor material that is then used in the mixingprocess with another precursor material.

These process types are described in this specification, among otherplaces, under their respective headings. It should be understood thatthe teachings for one process, under one heading, and the teachings forthe other processes, under the other headings, can be applicable to eachother, as well as, being applicable to other sections, embodiments andteachings in this specification, and vice versa. The starting orprecursor materials for one type of process may be used in the othertype of processes. Further, it should be understood that the processesdescribed under these headings should be read in context with theentirely of this specification, including the various examples andembodiments.

It should be understood that combinations and variations of theseprocesses may be used in reaching a precursor formulation, and inreaching intermediate, end and final products. Depending upon thespecific process and desired features of the product the precursors andstarting materials for one process type can be used in the other. Aformulation from the mixing type process may be used as a precursor, orcomponent in the reaction type process, or the reaction blending typeprocess. Similarly, a formulation from the reaction type process may beused in the mixing type process and the reaction blending process.Similarly, a formulation from the reaction blending type process may beused in the mixing type process and the reaction type process. Thus, andpreferably, the optimum performance and features from the otherprocesses can be combined and utilized to provide a cost effective andefficient process and end product. These processes provide greatflexibility to create custom features for intermediate, end, and finalproducts, and thus, any of these processes, and combinations of them,can provide a specific predetermined product. In selecting which type ofprocess is preferable, factors such as cost, controllability, shelflife, scale up, manufacturing ease, etc., can be considered.

In addition to being commercially available the precursors may be madeby way of an alkoxylation type process, e.g., an ethoxylation process.In this process chlorosilanes are reacted with ethanol in the presencesof a catalyst, e.g., HCl, to provide the precursor materials, whichmaterials may further be reacted to provide longer chain precursors.Other alcohols, e.g., methanol may also be used. Thus, for exampleSiCl₄, SiCl₃H, SiCl₂(CH₃)₂, SiCl₂(CH₃)H, Si(CH₃)₃Cl, Si(CH₃)ClH, arereacted with ethanol CH₃CH₂OH to form precursors. In some of thesereactions phenols may be the source of the phenoxy group, which issubstituted for a hydride group that has been placed on the silicon.One, two or more step reactions may need to take place.

Precursor materials may also be obtained by way of an acetylene reactionroute. In general there are several known paths for adding acetylene toSi—H. Thus, for example, tetramethylcyclotetrasiloxane can be reactedwith acetylene in the presence of a catalyst to producetetramethyltetravinylcyclotetrasiloxane. This product can then be ringopened and polymerized in order to form linear vinyl, methylsiloxanes.Alternatively, typical vinyl silanes can be produced by reactingmethyl,dichlorosilane (obtained from the direct process or Rochowprocess) with acetylene. These monomers can then be purified (becausethere maybe some scrambling) to form vinyl, methyl, dichlorosilane. Thenthe vinyl monomer can be polymerized via hydrolysis to form many cyclic,and linear siloxanes, having various chain lengths, including forexample various cyclotetrasiloxanes (e.g., D₄′) and variouscyclopentasiloxanes (e.g., D₅′). These paths, however, are costly, andthere has been a long standing and increasing need for a lower cost rawmaterial source to produce vinyl silanes. Prior to the presentinventions, it was not believed that MHF could be used in an acetyleneaddition process to obtain vinyl silanes. MHF is less expensive thanvinyl, methyl (either linear or cyclic), and adding acetylene to MHF tomake vinyl meets, among other things, the long standing need to providea more cost effective material and at relatively inexpensive costs. Inmaking this addition the following variables, among others, should beconsidered and controlled: feed (D₄′, linear methyl, hydrogen siloxanefluids); temperature; ratio of acetylene to Si—H; homogeneous catalysts(Karstedt's, Dibutyltindilaureate, no catalyst, Karstedt's withinhibitor, chloroplatinic acid, ashby's); supported catalysts (Pt oncarbon, Pt on alumina, Pd on alumina); flow rates (liquid feed,acetylene feed); pressure; and, catalyst concentration. Examples ofembodiments of reactions providing for the addition of acetylene to MHF(cyclic and linear) are provided in Tables A and B. Table A are batchacetylene reactions. Table B are continuous acetylene reactions. Itshould be understood that batch, continuous, counter current flow of MHFand acetylene feeds, continuous recycle of single pass material toachieve higher conversions, and combinations and variations of these andother processes can be utilized.

TABLE A Batch Acetylene Reactions Methyl Amount of Acetylene ReactionAcetyl Mol % Hydride Catalyst % Solvent Temp Flow Time (rel to Total RunSi—H (grams) (rel to MeH) Inhibitor Solvent (grams) (° C.) (ccm) (hrs)Hydride) 1 MHF 400 0.48% 0.00% — —  80-100 — 0.20 — 2 MHF 1000 0.27%0.00% — — 65-75 276-328 0.75 3.4% 3 MHF 1000 0.00% 0.00% — — 80 378-7296.33 49.4% 100  120  4 MHF 117 0.20% 0.00% Hexane 1000  60-66 155-2424.50 188.0% 5 MHF 1000 0.40% 0.40% — — 55-90 102 7.5 15.7% 6 MHF 3601.00% 0.00% Hexane 392 65 102 6.4 40.3% 7a MHF 360 0.40% 0.00% Hexane400 65 — 2.0 23.4% 7b MHF 280 0.40% 0.00% Hexane 454 68 — 137.0 23.4% 8D4′ 1000 0.27% 0.00% — — 79 327-745 6.5 61.3% 9 MHF 370 0.40% 0.00%Hexane 402 65 155-412 8.0 140.3%

TABLE B Continuous Acetylene Reactions Reactor Reactor Acetyl Mol %Catalyst % Silane Conc Temp Pressure (rel to Total Run Si—H (rel to MeH)Inhibitor (wt %) Solvent (° C.) (psig) Hydride) 10 D4′ 5% Pt on 0.00%100.0% —  60-100 50 40.0% Carbon 11 D4′ 5% Pt on 0.00% 100.0% — 50-90100  20.0% Carbon 12 D4′ 1% Pt on 0.00% 100.0% — 40-50 50 23.8% Alumina13 MHF 5% Pt on 0.00% 100.0% — 55-60 55-60 13.6% Carbon 14 MHF 0.01% Pton 0.00% 20.0% Hexane 20-25 50 108.5% Alumina 15 MHF 0.01% Pt on 0.00%20.0% Hexane 60 50-55 117.1% Alumina 16 MHF 0.01% Pt on 0.00% 20.0%Hexane 70 50 125.1% Alumina 17 MHF 0.12% Pt on 0.00% 20.0% Hexane 60 50133.8% Alumina 18 MHF 0.12% Pt on 0.00% 4.0% Hexane 60 50 456.0% Alumina(D4′ is tetramethyl tetrahydride cyclotetrasiloxane)

Continuous High Pressure Reactor (“CHPR”) embodiments may beadvantageous for, among other reasons: reaction conversion saving moreacetylene needed in liquid phase; tube reactors providing pressureswhich in turn increases solubility of acetylene; reaction with hexynesaving concentration and time (e.g., 100 hours); can eliminatehomogeneous catalyst and thus eliminate hydrosilylation reaction withresultant vinyls once complete; and, using a heterogeneous (Solid)catalyst to maintain product integrity, increased shelf-life, increasepot-life and combinations and variations of these.

In addressing the various conditions in the acetylene additionreactions, some factors may be: crosslinking retardation by dilution,acetylene and lower catalyst concentration; and conversion (usingheterogeneous catalyst) may be lower for larger linear moleculescompared to smaller molecules.

The presence and quality of vinyl and vinyl conversions can bedetermined by, among other things: FT-IR for presence of vinylabsorptions, decrease in SiH absorption; ¹H NMR for presence of vinylsand decrease in SiH; ¹³C NMR for presence of vinyls.

As used herein, unless specified otherwise the terms %, weight % andmass % are used interchangeably and refer to the weight of a firstcomponent as a percentage of the weight of the total, e.g., formulation,mixture, material or product. As used herein, unless specified otherwise“volume %” and “% volume” and similar such terms refer to the volume ofa first component as a percentage of the volume of the total, e.g.,formulation, material or product.

The Mixing Type Process

Precursor materials may be methyl hydrogen, and substituted and modifiedmethyl hydrogens, siloxane backbone additives, reactive monomers,reaction products of a siloxane backbone additive with a silane modifieror an organic modifier, and other similar types of materials, such assilane based materials, silazane based materials, carbosilane basedmaterials, phenol/formaldehyde based materials, and combinations andvariations of these. The precursors are preferably liquids at roomtemperature, although they may be solids that are melted, or that aresoluble in one of the other precursors. (In this situation, however, itshould be understood that when one precursor dissolves another, it isnevertheless not considered to be a “solvent” as that term is used withrespect to the prior art processes that employ non-constituent solvents,e.g., solvents that do not form a part or component of the end product,are treated as waste products, and both.)

The precursors are mixed together in a vessel, preferably at roomtemperature. Preferably, little, and more preferably no solvents, e.g.,water, organic solvents, polar solvents, non-polar solvents, hexane,THF, toluene, are added to this mixture of precursor materials.Preferably, each precursor material is miscible with the others, e.g.,they can be mixed at any relative amounts, or in any proportions, andwill not separate or precipitate. At this point the “precursor mixture”or “polysilocarb precursor formulation” is compete (noting that if onlya single precursor is used the material would simply be a “polysilocarbprecursor” or a “polysilocarb precursor formulation” or a“formulation”). Although complete, fillers and reinforcers may be addedto the formulation. In preferred embodiments of the formulation,essentially no, and more preferably no chemical reactions, e.g.,crosslinking or polymerization, takes place within the formulation, whenthe formulation is mixed, or when the formulation is being held in avessel, on a prepreg, or over a time period, prior to being cured.

The precursors can be mixed under numerous types of atmospheres andconditions, e.g., air, inert, N₂, Argon, flowing gas, static gas,reduced pressure, elevated pressure, ambient pressure, and combinationsand variations of these.

Additionally, inhibitors such as cyclohexane, 1-Ethynyl-1-cyclohexanol(which may be obtained from ALDRICH), Octamethylcyclotetrasiloxane, andtetramethyltetravinylcyclotetrasiloxane, may be added to thepolysilocarb precursor formulation, e.g., an inhibited polysilocarbprecursor formulation. It should be noted thattetramethyltetravinylcyclotetrasiloxane may act as both a reactant and areaction retardant (e.g., an inhibitor), depending upon the amountpresent and temperature, e.g., at room temperature it is a retardant andat elevated temperatures it is a reactant. Other materials, as well, maybe added to the polysilocarb precursor formulation, e.g., a filledpolysilocarb precursor formulation, at this point in processing,including fillers such as SiC powder, carbon black, sand, polymerderived ceramic particles, pigments, particles, nano-tubes, whiskers, orother materials, discussed in this specification or otherwise known tothe arts. Further, a formulation with both inhibitors and fillers wouldbe considered an inhibited, filled polysilocarb precursor formulation.

Depending upon the particular precursors and their relative amounts inthe polysilocarb precursor formulation, polysilocarb precursorformulations may have shelf lives at room temperature of greater than 12hours, greater than 1 day, greater than 1 week, greater than 1 month,and for years or more. These precursor formulations may have shelf livesat high temperatures, for example, at about 90° F., of greater than 12hours, greater than 1 day, greater than 1 week, greater than 1 month,and for years or more. The use of inhibitors may further extend theshelf life in time, for higher temperatures, and combinations andvariations of these. The use of inhibitors, may also have benefits inthe development of manufacturing and commercial processes, bycontrolling the rate of reaction, so that it takes place in the desiredand intended parts of the process or manufacturing system.

As used herein the term “shelf life” should be given its broadestpossible meaning, unless specified otherwise, and would include, forexample, the formulation being capable of being used for its intendedpurpose, or performing, e.g., functioning, for its intended use, at 100%percent as well as a freshly made formulation, at least about 90% aswell as a freshly made formulation, at least about 80% as well as afreshly made formulation, and at at least about 70% as well as a freshlymade formulation.

Precursors and precursor formulations are preferably non-hazardousmaterials. They have flash points that are preferably above about 70°C., above about 80° C., above about 100° C. and above about 300° C., andabove. Preferably, they may be noncorrosive. Preferably, they may have alow vapor pressure, may have low or no odor, and may be non- or mildlyirritating to the skin.

A catalyst or initiator may be used, and can be added at the time of,prior to, shortly before, or at an earlier time before the precursorformulation is formed or made into a structure, prior to curing. Thecatalysis assists in, advances, and promotes the curing of the precursorformulation to form a preform.

The time period where the precursor formulation remains useful forcuring after the catalysis is added is referred to as “pot life”, e.g.,how long can the catalyzed formulation remain in its holding vesselbefore it should be used. Depending upon the particular formulation,whether an inhibitor is being used, and if so the amount being used,storage conditions, e.g., temperature, low O₂ atmosphere, andpotentially other factors, precursor formulations can have pot lives,for example, of from about 5 minutes to about 10 days, about 1 day toabout 6 days, about 4 to 5 days, about 30 minutes, about 15 minutes,about 1 hour to about 24 hours, and about 12 hours to about 24 hours.

The catalyst can be any platinum (Pt) based catalyst, which can, forexample, be diluted to a ranges of: about 0.01 parts per million (ppm)Pt to about 250 ppm Pt, about 0.03 ppm Pt, about 0.1 ppm Pt, about 0.2ppm Pt, about 0.5 ppm Pt, about 0.02 to 0.5 ppm Pt, about 1 ppm to 200ppm Pt and preferably, for some applications and embodiments, about 5ppm to 50 ppm Pt. The catalyst can be a peroxide based catalyst with,for example, a 10 hour half life above 90 C at a concentration ofbetween 0.1% to 3% peroxide, and about 0.5% and 2% peroxide. It can bean organic based peroxide. It can be any organometallic catalyst capableof reacting with Si—H bonds, Si—OH bonds, or unsaturated carbon bonds,these catalysts may include: dibutyltin dilaurate, zinc octoate,peroxides, organometallic compounds of for example titanium, zirconium,rhodium, iridium, palladium, cobalt or nickel. Catalysts may also be anyother rhodium, rhenium, iridium, palladium, nickel, and ruthenium typeor based catalysts. Combinations and variations of these and othercatalysts may be used. Catalysts may be obtained from ARKEMA under thetrade name LUPEROX, e.g., LUPEROX 231; and from Johnson Matthey underthe trade names: Karstedt's catalyst, Ashby's catalyst, Speier'scatalyst.

Further, custom and specific combinations of these and other catalystsmay be used, such that they are matched to specific formulations, and inthis way selectively and specifically catalyze the reaction of specificconstituents. Moreover, the use of these types of matchedcatalyst-formulations systems may be used to provide predeterminedproduct features, such as for example, pore structures, porosity,densities, density profiles, high purity, ultra high purity, and othermorphologies or features of cured structures and ceramics.

In this mixing type process for making a precursor formulation,preferably chemical reactions or molecular rearrangements only takeplace during the making of the starting materials, the curing process,and in the pyrolizing process. Chemical reactions, e.g.,polymerizations, reductions, condensations, substitutions, take place orare utilized in the making of a starting material or precursor. Inmaking a polysilocarb precursor formulation by the mixing type process,preferably no and essentially no, chemical reactions and molecularrearrangements take place. These embodiments of the present mixing typeprocess, which avoid the need to, and do not, utilize a polymerizationor other reaction during the making of a precursor formulation, providessignificant advantages over prior methods of making polymer derivedceramics. Preferably, in the embodiments of these mixing type offormulations and processes, polymerization, crosslinking or otherchemical reactions take place primarily, preferably essentially, andmore preferably solely during the curing process.

The precursor may be a siloxane backbone additive, such as, methylhydrogen (MH), which formula is shown below.

The MH may have a molecular weight (“mw” which can be measured as weightaveraged molecular weight in amu or as g/mol) from about 400 mw to about10,000 mw, from about 600 mw to about 3,000 mw, and may have a viscositypreferably from about 20 cps to about 60 cps. The percentage ofmethylsiloxane units “X” may be from 1% to 100%. The percentage of thedimethylsiloxane units “Y” may be from 0% to 99%. This precursor may beused to provide the backbone of the cross-linked structures, as well as,other features and characteristics to the cured preform and ceramicmaterial. This precursor may also, among other things, be modified byreacting with unsaturated carbon compounds to produce new, oradditional, precursors. Typically, methyl hydrogen fluid (MHF) hasminimal amounts of “Y”, and more preferably “Y” is for all practicalpurposes zero.

The precursor may be a siloxane backbone additive, such as vinylsubstituted polydimethyl siloxane, which formula is shown below.

This precursor may have a molecular weight (mw) from about 400 mw toabout 10,000 mw, and may have a viscosity preferably from about 50 cpsto about 2,000 cps. The percentage of methylvinylsiloxane units “X” maybe from 1% to 100%. The percentage of the dimethylsiloxane units “Y” maybe from 0% to 99%. Preferably, X is about 100%. This precursor may beused to decrease cross-link density and improve toughness, as well as,other features and characteristics to the cured preform and ceramicmaterial.

The precursor may be a siloxane backbone additive, such as vinylsubstituted and vinyl terminated polydimethyl siloxane, which formula isshown below.

This precursor may have a molecular weight (mw) from about 500 mw toabout 15,000 mw, and may preferably have a molecular weight from about500 mw to 1,000 mw, and may have a viscosity preferably from about 10cps to about 200 cps. The percentage of methylvinylsiloxane units “X”may be from 1% to 100%. The percentage of the dimethylsiloxane units “Y”may be from 0% to 99%. This precursor may be used to provide branchingand decrease the cure temperature, as well as, other features andcharacteristics to the cured preform and ceramic material.

The precursor may be a siloxane backbone additive, such as vinylsubstituted and hydrogen terminated polydimethyl siloxane, which formulais shown below.

This precursor may have a molecular weight (mw) from about 300 mw toabout 10,000 mw, and may preferably have a molecular weight from about400 mw to 800 mw, and may have a viscosity preferably from about 20 cpsto about 300 cps. The percentage of methylvinylsiloxane units “X” may befrom 1% to 100%. The percentage of the dimethylsiloxane units “Y” may befrom 0% to 99%. This precursor may be used to provide branching anddecrease the cure temperature, as well as, other features andcharacteristics to the cured preform and ceramic material.

The precursor may be a siloxane backbone additive, such as allylterminated polydimethyl siloxane, which formula is shown below.

This precursor may have a molecular weight (mw) from about 400 mw toabout 10,000 mw, and may have a viscosity preferably from about 40 cpsto about 400 cps. The repeating units are the same. This precursor maybe used to provide UV curability and to extend the polymeric chain, aswell as, other features and characteristics to the cured preform andceramic material.

The precursor may be a siloxane backbone additive, such as vinylterminated polydimethyl siloxane, which formula is shown below.

This precursor may have a molecular weight (mw) from about 200 mw toabout 5,000 mw, and may preferably have a molecular weight from about400 mw to 1,500 mw, and may have a viscosity preferably from about 10cps to about 400 cps. The repeating units are the same. This precursormay be used to provide a polymeric chain extender, improve toughness andto lower cure temperature down to for example room temperature curing,as well as, other features and characteristics to the cured preform andceramic material.

The precursor may be a siloxane backbone additive, such as silanol(hydroxy) terminated polydimethyl siloxane, which formula is shownbelow.

This precursor may have a molecular weight (mw) from about 400 mw toabout 10,000 mw, and may preferably have a molecular weight from about600 mw to 1,000 mw, and may have a viscosity preferably from about 30cps to about 400 cps. The repeating units are the same. This precursormay be used to provide a polymeric chain extender, a tougheningmechanism, can generate nano- and micro-scale porosity, and allowscuring at room temperature, as well as other features andcharacteristics to the cured preform and ceramic material.

The precursor may be a siloxane backbone additive, such as silanol(hydroxy) terminated vinyl substituted dimethyl siloxane, which formulais shown below.

This precursor may have a molecular weight (mw) from about 400 mw toabout 10,000 mw, and may preferably have a molecular weight from about600 mw to 1,000 mw, and may have a viscosity preferably from about 30cps to about 400 cps. The percentage of methylvinylsiloxane units “X”may be from 1% to 100%. The percentage of the dimethylsiloxane units “Y”may be from 0% to 99%. This precursor may be used, among other things,in a dual-cure system; in this manner the dual-cure can allow the use ofmultiple cure mechanisms in a single formulation. For example, bothcondensation type cure and addition type cure can be utilized. This, inturn, provides the ability to have complex cure profiles, which forexample may provide for an initial cure via one type of curing and afinal cure via a separate type of curing.

The precursor may be a siloxane backbone additive, such as hydrogen(hydride) terminated polydimethyl siloxane, which formula is shownbelow.

This precursor may have a molecular weight (mw) from about 200 mw toabout 10,000 mw, and may preferably have a molecular weight from about500 mw to 1,500 mw, and may have a viscosity preferably from about 20cps to about 400 cps. The repeating units are the same. This precursormay be used to provide a polymeric chain extender, as a tougheningagent, and it allows lower temperature curing, e.g., room temperature,as well as, other features and characteristics to the cured preform andceramic material.

The precursor may be a siloxane backbone additive, such as di-phenylterminated siloxane (which may also be referred to as phenylterminated), which formula is shown below.

Where here R is a reactive group, such as vinyl, hydroxy, or hydride.This precursor may have a molecular weight (mw) from about 500 mw toabout 2,000 mw, and may have a viscosity preferably from about 80 cps toabout 300 cps. The percentage of methyl-R-siloxane units “X” may be from1% to 100%. The percentage of the dimethylsiloxane units “Y” may be from0% to 99%. This precursor may be used to provide a toughening agent, andto adjust the refractive index of the polymer to match the refractiveindex of various types of glass, to provide for example transparentfiberglass, as well as, other features and characteristics to the curedpreform and ceramic material.

The precursor may be a siloxane backbone additive, such as a mono-phenylterminated siloxane (which may also be referred to as trimethylterminated, phenyl terminated siloxane), which formulas are shown below.

Where R is a reactive group, such as vinyl, hydroxy, or hydride. Thisprecursor may have a molecular weight (mw) from about 500 mw to about2,000 mw, and may have a viscosity preferably from about 80 cps to about300 cps. The percentage of methyl-R-siloxane units “X” may be from 1% to100%. The percentage of the dimethylsiloxane units “Y” may be from 0% to99%. This precursor may be used to provide a toughening agent and toadjust the refractive index of the polymer to match the refractive indexof various types of glass, to provide for example transparentfiberglass, as well as, other features and characteristics to the curedpreform and ceramic material.

The precursor may be a siloxane backbone additive, such as diphenyldimethyl polysiloxane, which formula is shown below.

This precursor may have a molecular weight (mw) from about 500 mw toabout 20,000 mw, and may have a molecular weight from about 800 to about4,000, and may have a viscosity preferably from about 100 cps to about800 cps. The percentage of dimethylsiloxane units “X” may be from 25% to95%. The percentage of the diphenyl siloxane units “Y” may be from 5% to75%. This precursor may be used to provide similar characteristics tothe mono-phenyl terminated siloxane, as well as, other features andcharacteristics to the cured preform and ceramic material.

The precursor may be a siloxane backbone additive, such as vinylterminated diphenyl dimethyl polysiloxane, which formula is shown below.

This precursor may have a molecular weight (mw) from about 400 mw toabout 20,000 mw, and may have a molecular weight from about 800 to about2,000, and may have a viscosity preferably from about 80 cps to about600 cps. The percentage of dimethylsiloxane units “X” may be from 25% to95%. The percentage of the diphenyl siloxane units “Y” may be from 5% to75%. This precursor may be used to provide chain extension, tougheningagent, changed or altered refractive index, and improvements to hightemperature thermal stability of the cured material, as well as, otherfeatures and characteristics to the cured preform and ceramic material.

The precursor may be a siloxane backbone additive, such as hydroxyterminated diphenyl dimethyl polysiloxane, which formula is shown below.

This precursor may have a molecular weight (mw) from about 400 mw toabout 20,000 mw, and may have a molecular weight from about 800 to about2,000, and may have a viscosity preferably from about 80 cps to about400 cps. The percentage of dimethylsiloxane units “X” may be from 25% to95%. The percentage of the diphenyl siloxane units “Y” may be from 5% to75%. This precursor may be used to provide chain extension, tougheningagent, changed or altered refractive index, and improvements to hightemperature thermal stability of the cured material, can generate nano-and micro-scale porosity, as well as other features and characteristicsto the cured preform and ceramic material.

This precursor may be a siloxane backbone additive, such as methylterminated phenylethyl polysiloxane, (which may also be referred to asstyrene vinyl benzene dimethyl polysiloxane), which formula is shownbelow.

This precursor may have a molecular weight (mw) may be from about 800 mwto at least about 10,000 mw to at least about 20,000 mw, and may have aviscosity preferably from about 50 cps to about 350 cps. The percentageof styrene vinyl benzene siloxane units “X” may be from 1% to 60%. Thepercentage of the dimethylsiloxane units “Y” may be from 40% to 99%.This precursor may be used to provide improved toughness, decreasesreaction cure exotherm, may change or alter the refractive index, adjustthe refractive index of the polymer to match the refractive index ofvarious types of glass, to provide for example transparent fiberglass,as well as, other features and characteristics to the cured preform andceramic material.

A variety of cyclosiloxanes can be used as reactive molecules in theformulation. They can be described by the following nomenclature systemor formula: D_(x)D*_(y), where “D” represents a dimethyl siloxy unit and“D*” represents a substituted methyl siloxy unit, where the “*” groupcould be vinyl, allyl, hydride, hydroxy, phenyl, styryl, alkyl,cyclopentadienyl, or other organic group, x is from 0-8, y is >=1, andx+y is from 3-8.

The precursor batch may also contain non-silicon based cross-linkingagents, be the reaction product of a non-silicon based cross linkingagent and a siloxane backbone additive, and combinations and variationof these. The non-silicon based cross-linking agents are intended to,and provide, the capability to cross-link during curing. For example,non-silicon based cross-linking agents that can be used include:cyclopentadiene (CP), methylcyclopentadiene (MeCP), dicyclopentadiene(“DCPD”), methyldicyclopentadiene (MeDCPD), tricyclopentadiene (TCPD),piperylene, divnylbenzene, isoprene, norbornadiene, vinylnorbornene,propenylnorbornene, isopropenylnorbornene, methylvinylnorbornene,bicyclononadiene, methylbicyclononadiene, propadiene,4-vinylcyclohexene, 1,3-heptadiene, cycloheptadiene, 1,3-butadiene,cyclooctadiene and isomers thereof. Generally, any hydrocarbon thatcontains two (or more) unsaturated, C═C, bonds that can react with aSi—H, Si—OH, or other Si bond in a precursor, can be used as across-linking agent. Some organic materials containing oxygen, nitrogen,and sulphur may also function as cross-linking moieties.

The precursor may be a reactive monomer. These would include molecules,such as tetramethyltetravinylcyclotetrasiloxane (“TV”), which formula isshown below.

This precursor may be used to provide a branching agent, athree-dimensional cross-linking agent, as well as, other features andcharacteristics to the cured preform and ceramic material. (It is alsonoted that in certain formulations, e.g., above 2%, and certaintemperatures, e.g., about from about room temperature to about 60° C.,this precursor may act as an inhibitor to cross-linking, e.g., in mayinhibit the cross-linking of hydride and vinyl groups.)

The precursor may be a reactive monomer, for example, such as trivinylcyclotetrasiloxane,

divinyl cyclotetrasiloxane,

trivinyl monohydride cyclotetrasiloxane,

divinyl dihydride cyclotetrasiloxane,

and a hexamethyl cyclotetrasiloxane, such as,

The precursor may be a silane modifier, such as vinyl phenyl methylsilane, diphenyl silane, diphenyl methyl silane, and phenyl methylsilane (some of which may be used as an end capper or end terminationgroup). These silane modifiers can provide chain extenders and branchingagents. They also improve toughness, alter refractive index, and improvehigh temperature cure stability of the cured material, as well asimproving the strength of the cured material, among other things. Aprecursor, such as diphenyl methyl silane, may function as an endcapping agent, that may also improve toughness, alter refractive index,and improve high temperature cure stability of the cured material, aswell as, improving the strength of the cured material, among otherthings.

The precursor may be a reaction product of a silane modifier with avinyl terminated siloxane backbone additive. The precursor may be areaction product of a silane modifier with a hydroxy terminated siloxanebackbone additive. The precursor may be a reaction product of a silanemodifier with a hydride terminated siloxane backbone additive. Theprecursor may be a reaction product of a silane modifier with TV. Theprecursor may be a reaction product of a silane. The precursor may be areaction product of a silane modifier with a cyclosiloxane, taking intoconsideration steric hindrances. The precursor may be a partiallyhydrolyzed tertraethyl orthosilicate, such as TES 40 or Silbond 40. Theprecursor may also be a methylsesquisiloxane such as SR-350 availablefrom General Electric Company, Wilton, Conn. The precursor may also be aphenyl methyl siloxane such as 604 from Wacker Chemie AG. The precursormay also be a methylphenylvinylsiloxane, such as H62 C from WackerChemie AG.

The precursors may also be selected from the following: SiSiB® HF2020,TRIMETHYLSILYL TERMINATED METHYL HYDROGEN SILICONE FLUID 63148-57-2;SiSiB® HF2050 TRIMETHYLSILYL TERMINATED METHYLHYDROSILOXANEDIMETHYLSILOXANE COPOLYMER 68037-59-2; SiSiB® HF2060 HYDRIDE TERMINATEDMETHYLHYDROSILOXANE DIMETHYLSILOXANE COPOLYMER 69013-23-6; SiSiB® HF2038HYDROGEN TERMINATED POLYDIPHENYL SILOXANE; SiSiB® HF2068 HYDRIDETERMINATED METHYLHYDROSILOXANE DIMETHYLSILOXANE COPOLYMER 115487-49-5;SiSiB® HF2078 HYDRIDE TERMINATED POLY(PHENYLDIMETHYLSILOXY) SILOXANEPHENYL SILSESQUIOXANE, HYDROGEN-TERMINATED 68952-30-7; SiSiB® VF6060VINYLDIMETHYL TERMINATED VINYLMETHYL DIMETHYL POLYSILOXANE COPOLYMERS68083-18-1; SiSiB® VF6862 VINYLDIMETHYL TERMINATED DIMETHYL DIPHENYLPOLYSILOXANE COPOLYMER 68951-96-2; SiSiB® VF6872 VINYLDIMETHYLTERMINATED DIMETHYL-METHYLVINYL-DIPHENYL POLYSILOXANE COPOLYMER; SiSiB®PC9401 1,1,3,3-TETRAMETHYL-1,3-DIVINYLDISILOXANE 2627-95-4; SiSiB®PF1070 SILANOL TERMINATED POLYDIMETHYLSILOXANE (OF1070) 70131-67-8;SiSiB® OF1070 SILANOL TERMINATED POLYDIMETHYSILOXANE 70131-67-8;OH-ENDCAPPED POLYDIMETHYLSILOXANE HYDROXY TERMINATED OLYDIMETHYLSILOXANE73138-87-1; SiSiB® VF6030 VINYL TERMINATED POLYDIMETHYL SILOXANE68083-19-2; and, SiSiB® HF2030 HYDROGEN TERMINATED POLYDIMETHYLSILOXANEFLUID 70900-21-9.

Thus, in additional to the forgoing type of precursors, it iscontemplated that a precursor may be a compound of the following generalformula.

Wherein end cappers E₁ and E₂ are chosen from groups such as trimethylsilicon (—Si(CH₃)₃), dimethyl silicon hydroxy (—Si(CH₃)₂OH), dimethylsilicon hydride (—Si(CH₃)₂H), dimethyl vinyl silicon(—Si(CH₃)₂(CH═CH₂)), (—Si(CH₃)₂(C₆H₅)) and dimethyl alkoxy silicon(—Si(CH₃)₂(OR). The R groups R₁, R₂, R₃, and R₄ may all be different, orone or more may be the same. Thus, for example, R₂ is the same as R₃, R₃is the same as R₄, R₁ and R₂ are different with R₃ and R₄ being thesame, etc. The R groups are chosen from groups such as hydride (—H),methyl (Me)(—C), ethyl (—C—C), vinyl (—C═C), alkyl (—R)(C_(n)H_(2n+1)),allyl (—C—C═C), aryl (′R), phenyl (Ph)(—C₆H₅), methoxy (—O—C), ethoxy(—O—C—C), siloxy (—O—Si—R₃), alkoxy (—O—R), hydroxy (—O—H), phenylethyl(—C—C—C₆H₅) and methyl,phenyl-ethyl (—C—C(—C)(—C₆H₅).

In general, embodiments of formulations for polysilocarb formulationsmay for example have from about 0% to 50% MH, about 20% to about 99% MH,about 0% to about 30% siloxane backbone additives, about 1% to about 60%reactive monomers, about 30% to about 100% TV, and, about 0% to about90% reaction products of a siloxane backbone additives with a silanemodifier or an organic modifier reaction products.

In mixing the formulations sufficient time should be used to permit theprecursors to become effectively mixed and dispersed. Generally, mixingof about 15 minutes to an hour is sufficient. Typically, the precursorformulations are relatively, and essentially, shear insensitive, andthus the type of pumps or mixing are not critical. It is further notedthat in higher viscosity formulations additional mixing time may berequired. The temperature of the formulations, during mixing shouldpreferably be kept below about 45° C., and preferably about 10° C. (Itis noted that these mixing conditions are for the pre-catalyzedformulations.)

The Reaction Type Process

In the reaction type process, in general, a chemical reaction is used tocombine one, two or more precursors, typically in the presence of asolvent, to form a precursor formulation that is essentially made up ofa single polymer that can then be, catalyzed, cured and pyrolized. Thisprocess provides the ability to build custom precursor formulations thatwhen cured can provide plastics having unique and desirable featuressuch as high temperature, flame resistance and retardation, strength andother features. The cured materials can also be pyrolized to formceramics having unique features. The reaction type process allows forthe predetermined balancing of different types of functionality in theend product by selecting functional groups for incorporation into thepolymer that makes up the precursor formulation, e.g., phenyls whichtypically are not used for ceramics but have benefits for providing hightemperature capabilities for plastics, and styrene which typically doesnot provide high temperature features for plastics but provides benefitsfor ceramics.

In general a custom polymer for use as a precursor formulation is madeby reacting precursors in a condensation reaction to form the polymerprecursor formulation. This precursor formulation is then cured into apreform through a hydrolysis reaction. The condensation reaction forms apolymer of the type shown below.

Where R₁ and R₂ in the polymeric units can be a hydride (—H), a methyl(Me)(—C), an ethyl (—C—C), a vinyl (—C═C), an alkyl (—R)(C_(n)H_(2n+1)),an unsaturated alkyl (—C_(n)H_(2n−1)), a cyclic alkyl (—C_(n)H_(2n−1)),an allyl (—C—C═C), a butenyl (—C₄H₇), a pentenyl (—C₅H₉), acyclopentenyl (—C₅H₇), a methyl cyclopentenyl (—C₅H₆(CH₃)), anorbornenyl (—C_(X)H_(Y), where X=7—15 and Y=9-18), an aryl (′R), aphenyl (Ph)(—C₆H₅), a cycloheptenyl (—C₇H₁₁), a cyclooctenyl (—C₈H₁₃),an ethoxy (—O—C—C), a siloxy (—O—Si—R₃), a methoxy (—O—C), an alkoxy,(—O—R), a hydroxy, (—O—H), a phenylethyl (—C—C—C₆H₅) amethyl,phenyl-ethyl (—C—C(—C)(—C₆H₅)) and a vinylphenyl-ethyl(—C—C(C₆H₄(—C═C))). R₁ and R₂ may be the same or different. The customprecursor polymers can have several different polymeric units, e.g., A₁,A₂, A_(n), and may include as many as 10, 20 or more units, or it maycontain only a single unit, for example, MHF made by the reactionprocess may have only a single unit.

Embodiments may include precursors, which include among others, atriethoxy methyl silane, a diethoxy methyl phenyl silane, a diethoxymethyl hydride silane, a diethoxy methyl vinyl silane, a dimethyl ethoxyvinyl silane, a diethoxy dimethyl silane. an ethoxy dimethyl phenylsilane, a diethoxy dihydride silane, a triethoxy phenyl silane, adiethoxy hydride trimethyl siloxane, a diethoxy methyl trimethylsiloxane, a trimethyl ethoxy silane, a diphenyl diethoxy silane, adimethyl ethoxy hydride siloxane, and combinations and variations ofthese and other precursors, including other precursors set forth in thisspecification.

The end units, Si End 1 and Si End 2, can come from the precursors ofdimethyl ethoxy vinyl silane, ethoxy dimethyl phenyl silane, andtrimethyl ethoxy silane. Additionally, if the polymerization process isproperly controlled a hydroxy end cap can be obtained from theprecursors used to provide the repeating units of the polymer.

In general, the precursors are added to a vessel with ethanol (or othermaterial to absorb heat, e.g., to provide thermal mass), an excess ofwater, and hydrochloric acid (or other proton source). This mixture isheated until it reaches its activation energy, after which the reactiontypically is exothermic. Generally, in this reaction the water reactswith an ethoxy group of the silicon of the precursor monomer, forming ahydroxy (with ethanol as the byproduct). Once formed this hydroxybecomes subject to reaction with an ethoxy group on the silicon ofanother precursor monomer, resulting in a polymerization reaction. Thispolymerization reaction is continued until the desired chain length(s)is built.

Control factors for determining chain length, among others, are: themonomers chosen (generally, the smaller the monomers the more that canbe added before they begin to coil around and bond to themselves); theamount and point in the reaction where end cappers are introduced; andthe amount of water and the rate of addition, among others. Thus, thechain lengths can be from about 180 mw (viscosity about 5 cps) to about65,000 mw (viscosity of about 10,000 cps), greater than about 1000 mw,greater than about 10,000 mw, greater than about 50,000 mw and greater.Further, the polymerized precursor formulation may, and typically does,have polymers of different molecular weights, which can be predeterminedto provide formulation, cured, and ceramic product performance features.

Upon completion of the polymerization reaction the material istransferred into a separation apparatus, e.g., a separation funnel,which has an amount of deionized water that, for example, is from about1.2× to about 1.5× the mass of the material. This mixture is vigorouslystirred for about less than 1 minute and preferably from about 5 to 30seconds. Once stirred the material is allowed to settle and separate,which may take from about 1 to 2 hours. The polymer is the higherdensity material and is removed from the vessel. This removed polymer isthen dried by either warming in a shallow tray at 90° C. for about twohours; or, preferably, is passed through a wiped film distillationapparatus, to remove any residual water and ethanol. Alternatively,sodium bicarbonate sufficient to buffer the aqueous layer to a pH ofabout 4 to about 7 is added. It is further understood that other, andcommercial, manners of mixing, reacting and separating the polymer fromthe material may be employed.

Preferably a catalyst is used in the curing process of the polymerprecursor formulations from the reaction type process. The samepolymers, as used for curing the precursor formulations from the mixingtype process can be used. It is noted that, generally unlike the mixingtype formulations, a catalyst is not necessarily required to cure areaction type polymer. Inhibitors may also be used. However, if acatalyst is not used, reaction time and rates will be slower. The curingand the pyrolysis of the cured material from the reaction process isessentially the same as the curing and pyrolysis of the cured materialfrom the mixing process and the reaction blending process.

The reaction type process can be conducted under numerous types ofatmospheres and conditions, e.g., air, inert, N₂, Argon, flowing gas,static gas, reduced pressure, ambient pressure, elevated pressure, andcombinations and variations of these.

The Reaction Blending Type Process

In the reaction blending type process precursor are reacted to from aprecursor formulation, in the absence of a solvent. For example, anembodiment of a reaction blending type process has a precursorformulation that is prepared from MHF and Dicyclopentadiene (“DCPD”).Using the reactive blending process a MHF/DCPD polymer is created andthis polymer is used as a precursor formulation. (It can be used aloneto form a cured or pyrolized product, or as a precursor in the mixing orreaction processes.) MHF of known molecular weight and hydrideequivalent mass; “P01” (P01 is a 2% Pt(0) tetravinylcyclotetrasiloxanecomplex in tetravinylcyclotetrasiloxane, diluted 20× withtetravinylcyclotetrasiloxane to 0.1% of Pt(0) complex. In this manner 10ppm Pt is provided for every 1% loading of bulk cat.) catalyst 0.20 wt %of MHF starting material (with known active equivalent weight), from 40to 90%; and Dicyclopentadiene with ≥83% purity, from 10 to 60% areutilized. In an embodiment of the process, a sealable reaction vessel,with a mixer, can be used for the reaction. The reaction is conducted inthe sealed vessel, in air; although other types of atmosphere can beutilized. Preferably, the reaction is conducted at atmospheric pressure,but higher and lower pressures can be utilized. Additionally, thereaction blending type process can be conducted under numerous types ofatmospheres and conditions, e.g., air, inert, N₂, Argon, flowing gas,static gas, reduced pressure, ambient pressure, elevated pressure, andcombinations and variations of these.

In an embodiment, 850 grams of MHF (85% of total polymer mixture) isadded to reaction vessel and heated to about 50° C. Once thistemperature is reached the heater is turned off, and 0.20% by weight P01Platinum catalyst is added to the MHF in the reaction vessel. Typically,upon addition of the catalyst bubbles will form and temp will initiallyrise approximately 2-20° C.

When the temperature begins to fall, about 150 g of DCPD (15 wt % oftotal polymer mixture) is added to the reaction vessel. The temperaturemay drop an additional amount, e.g., around 5-7° C.

At this point in the reaction process the temperature of the reactionvessel is controlled to, maintain a predetermined temperature profileover time, and to manage the temperature increase that may beaccompanied by an exotherm. Preferably, the temperature of the reactionvessel is regulated, monitored and controlled throughout the process.

In an embodiment of the MHF/DCPD embodiment of the reaction process, thetemperature profile can be as follows: let temperature reach about 80°C. (may take ˜15-40 min, depending upon the amount of materialspresent); temperature will then increase and peak at −104° C., as soonas temperature begins to drop, the heater set temperature is increasedto 100° C. and the temperature of the reaction mixture is monitored toensure the polymer temp stays above 80° C. for a minimum total of about2 hours and a maximum total of about 4 hours. After 2-4 hours above 80°C., the heater is turn off, and the polymer is cooled to ambient. Itbeing understood that in larger and smaller batches, continuous,semi-continuous, and other type processes the temperature and timeprofile may be different.

In larger scale, and commercial operations, batch, continuous, andcombinations of these, may be used. Industrial factory automation andcontrol systems can be utilized to control the reaction, temperatureprofiles and other processes during the reaction.

Table C sets forth various embodiments of reaction blending processes.

TABLE C Equiv- grams/ degree of Equivalents Equivalents EquivalentsEquivalents Equivalents alents mole of Material Name polymerizationSi/mole O/mole H/mol Vi/mol methyl/mole C/mole MW vinyltetramethylcyclotetrasiloxane 4 4 4 4 0 4 4 240.51 (D₄) MHF 33 35 34 330 39 39 2145.345 VMF 5 7 6 0 5 11 21 592.959 118.59 TV 4 4 4 0 4 4 12344.52 86.13 VT 0200 125 127 126 0 2 254 258 9451.206 4725.60 VT 0020 2426 25 0 2 52 56 1965.187 982.59 VT 0080 79 81 80 0 2 162 166 6041.7323020.87 Styrene 2 104.15 52.08 Dicyclopentadiene 2 132.2 66.101,4-divinylbenzene 2 130.19 65.10 isoprene 2 62.12 31.06 1,3 Butadiene 254.09 27.05 Catalyst 10 ppm Pt Catalyst LP 231

In the above table, the “degree of polymerization” is the number ofmonomer units, or repeat units, that are attached together to from thepolymer. “Equivalents _/mol” refers to the molar equivalents.“Grams/mole of vinyl” refers to the amount of a given polymer needed toprovide 1 molar equivalent of vinyl functionality. “VMH” refers tomethyl vinyl fluid, a linear vinyl material from the ethoxy process,which can be a substitute for TV. The numbers “0200” etc. for VT are theviscosity in centipoise for that particular VT.

Curing and Pyrolysis

Precursor formulations, including the polysiocarb precursor formulationsfrom the above types of processes, as well as others, can be cured toform a solid, semi-sold, or plastic like material. Typically, theprecursor formulations are spread, shaped, or otherwise formed into apreform, which would include any volumetric structure, or shape,including thin and thick films. In curing, the polysilocarb precursorformulation may be processed through an initial cure, to provide apartially cured material, which may also be referred to, for example, asa preform, green material, or green cure (not implying anything aboutthe material's color). The green material may then be further cured.Thus, one or more curing steps may be used. The material may be “endcured,” i.e., being cured to that point at which the material has thenecessary physical strength and other properties for its intendedpurpose. The amount of curing may be to a final cure (or “hard cure”),i.e., that point at which all, or essentially all, of the chemicalreaction has stopped (as measured, for example, by the absence ofreactive groups in the material, or the leveling off of the decrease inreactive groups over time). Thus, the material may be cured to varyingdegrees, depending upon its intended use and purpose. For example, insome situations the end cure and the hard cure may be the same. Curingconditions such as atmosphere and temperature may effect the compositionof the cured material.

In making the precursor formulation into a structure, or preform, theprecursor formulation, e.g., polysilocarb formulation, can be, forexample, formed using the following techniques: spraying, spray drying,atomization, nebulization, phase change separation, flowing, thermalspraying, drawing, dripping, forming droplets in liquid andliquid-surfactant systems, painting, molding, forming, extruding,spinning, ultrasound, vibrating, solution polymerization, emulsionpolymerization, micro-emuslion polymerization, injecting, injectionmolding, or otherwise manipulated into essentially any volumetric shape.These volumetric shapes may include for example, the following: spheres,pellets, rings, lenses, disks, panels, cones, frustoconical shapes,squares, rectangles, trusses, angles, channels, hollow sealed chambers,hollow spheres, blocks, sheets, coatings, films, skins, particulates,beams, rods, angles, slabs, columns, fibers, staple fibers, tubes, cups,pipes, and combinations and various of these and other more complexshapes, both engineering and architectural.

The forming step, the curing steps, and the pyrolysis steps may beconducted in batch processes, serially, continuously, with time delays(e.g., material is stored or held between steps), and combinations andvariations of these and other types of processing sequences. Further,the precursors can be partially cured, or the cure process can beinitiated and on going, prior to the precursor being formed into avolumetric shape. These steps, and their various combinations may be,and in some embodiments preferably are, conducted under controlled andpredetermined conditions (e.g., the material is exposed to apredetermined atmosphere, and temperature profile during the entirely ofits processing, e.g., reduced oxygen, temperature of cured preform heldat about 140° C. prior to pyrolysis). It should be further understoodthat the system, equipment, or processing steps, for forming, curing andpyrolizing may be the same equipment, continuous equipment, batch andlinked equipment, and combinations and variations of these and othertypes of industrial processes. Thus, for example, a spray dryingtechnique could form cured particles that are feed directly into afluidized bed reactor for pyrolysis.

The polysilocarb precursor formulations can be made into neat,non-reinforced, non-filled, composite, reinforced, and filledstructures, intermediates, end products, and combinations and variationsof these and other compositional types of materials. Further, thesestructures, intermediates and end products can be cured (e.g., greencured, end cured, or hard cured), uncured, pyrolized to a ceramic, andcombinations and variations of these (e.g., a cured material may befilled with pyrolized material derived from the same polysilocarb as thecured material).

The precursor formulations may be used to form a “neat” material, (by“neat” material it is meant that all, and essentially all of thestructure is made from the precursor material or unfilled formulation;and thus, there are no fillers or reinforcements).

The polysilocarb precursor formulations may be used to coat orimpregnate a woven or non-woven fabric, made from for example carbonfiber, glass fibers or fibers made from a polysilocarb precursorformulation (the same or different formulation), to from a prepregmaterial. Thus, the polysilocarb precursor formulations may be used toform composite materials, e.g., reinforced products. For example, theformulation may be flowed into, impregnated into, absorbed by orotherwise combined with a reinforcing material, such as carbon fibers,glass fiber, woven fabric, grapheme, carbon nanotubes, thin films,precipitates, sand, non-woven fabric, chopped fibers, fibers, rope,braided structures, ceramic powders, glass powders, carbon powders,graphite powders, ceramic fibers, metal powders, carbide pellets orcomponents, staple fibers, tow, nanostructures of the above, polymerderived ceramics, any other material that meets the temperaturerequirements of the process and end product, and combinations andvariations of these. The reinforcing material may also be made from, orderived from the same material as the formulation that has been formedinto a fiber and pyrolized into a ceramic, or it may be made from adifferent precursor formulation material, which has been formed into afiber and pyrolized into a ceramic.

The polysilocarb precursor formulation may be used to form a filledmaterial. A filled material would be any material having other solid, orsemi-solid, materials added to the polysilocarb precursor formulation.The filler material may be selected to provide certain features to thecured product, the ceramic product and both. These features may relateto, or be, for example, aesthetic, tactile, thermal, density, radiation,chemical, cost, magnetic, electric, and combinations and variations ofthese and other features. These features may be in addition to strength.Thus, the filler material may not affect the strength of the cured orceramic material, it may add strength, or could even reduce strength insome situations. The filler material could impart color, magneticcapabilities, fire resistances, flame retardance, heat resistance,electrical conductivity, anti-static, optical properties (e.g.,reflectivity, refractivity and iridescence), aesthetic properties (suchas stone like appearance in building products), chemical resistivity,corrosion resistance, wear resistance, reduced cost, abrasionsresistance, thermal insulation, UV stability, UV protective, and otherfeatures that may be desirable, necessary, and both, in the end productor material. Thus, filler materials could include carbon black, copperlead wires, thermal conductive fillers, electrically conductive fillers,lead, optical fibers, ceramic colorants, pigments, oxides, sand, dyes,powders, ceramic fines, polymer derived ceramic particles, pore-formers,carbosilanes, silanes, silazanes, silicon carbide, carbosilazanes,siloxane, powders, ceramic powders, metals, metal complexes, carbon,tow, fibers, staple fibers, boron containing materials, milled fibers,glass, glass fiber, fiber glass, and nanostructures (includingnanostructures of the forgoing) to name a few.

The polysilocarb formulation and products derived or made from thatformulation may have metals and metal complexes. Filled materials wouldinclude reinforced materials. In many cases, cured, as well as pyrolizedpolysilocarb filled materials can be viewed as composite materials.Generally, under this view, the polysilocarb would constitute the bulkor matrix phase, (e.g., a continuous, or substantially continuousphase), and the filler would constitute the dispersed (e.g.,non-continuous), phase. Depending upon the particular application,product or end use, the filler can be evenly distributed in theprecursor formulation, unevenly distributed, distributed over apredetermined and controlled distribution gradient (such as from apredetermined rate of settling), and can have different amounts indifferent formulations, which can then be formed into a product having apredetermined amounts of filler in predetermined areas (e.g., striatedlayers having different filler concentration). It should be noted,however, that by referring to a material as “filled” or “reinforced” itdoes not imply that the majority (either by weight, volume, or both) ofthat material is the polysilcocarb. Thus, generally, the ratio (eitherweight or volume) of polysilocarb to filler material could be from about0.1:99.9 to 99.9:0.1.

The polysilocarb precursor formulations may be used to formnon-reinforced materials, which are materials that are made ofprimarily, essentially, and preferably only from the precursormaterials; but may also include formulations having fillers or additivesthat do not impart strength.

The curing may be done at standard ambient temperature and pressure(“SATP”, 1 atmosphere, 25° C.), at temperatures above or below thattemperature, at pressures above or below that pressure, and over varyingtime periods. The curing can be conducted over various heatings, rate ofheating, and temperature profiles (e.g., hold times and temperatures,continuous temperature change, cycled temperature change, e.g., heatingfollowed by maintaining, cooling, reheating, etc.). The time for thecuring can be from a few seconds (e.g., less than about 1 second, lessthan 5 seconds), to less than a minute, to minutes, to hours, to days(or potentially longer). The curing may also be conducted in any type ofsurrounding environment, including for example, gas, liquid, air, water,surfactant containing liquid, inert atmospheres, N₂, Argon, flowing gas(e.g., sweep gas), static gas, reduced O₂, reduced pressure, elevatedpressure, ambient pressure, controlled partial pressure and combinationsand variations of these and other processing conditions. For high puritymaterials, the furnace, containers, handling equipment, atmosphere, andother components of the curing apparatus and process are clean,essentially free from, and do not contribute any elements or materials,that would be considered impurities or contaminants, to the curedmaterial. In an embodiment, the curing environment, e.g., the furnace,the atmosphere, the container and combinations and variations of thesecan have materials that contribute to or effect, for example, thecomposition, catalysis, stoichiometry, features, performance andcombinations and variations of these in the preform, the ceramic and thefinal applications or products.

Preferably, in embodiments of the curing process, the curing takes placeat temperatures in the range of from about 5° C. or more, from about 20°C. to about 250° C., from about 20° C. to about 150° C., from about 75°C. to about 125° C., and from about 80° C. to 90° C. Although higher andlower temperatures and various heating profiles, (e.g., rate oftemperature change over time (“ramp rate”, e.g., A degrees/time), holdtimes, and temperatures) can be utilized.

The cure conditions, e.g., temperature, time, ramp rate, may bedependent upon, and in some embodiments can be predetermined, in wholeor in part, by the formulation to match, for example the size of thepreform, the shape of the preform, or the mold holding the preform toprevent stress cracking, off gassing, or other phenomena associated withthe curing process. Further, the curing conditions may be such as totake advantage of, preferably in a controlled manner, what may havepreviously been perceived as problems associated with the curingprocess. Thus, for example, off gassing may be used to create a foammaterial having either open or closed structure. Similarly, curingconditions can be used to create or control the microstructure and thenanostructure of the material. In general, the curing conditions can beused to affect, control or modify the kinetics and thermodynamics of theprocess, which can affect morphology, performance, features andfunctions, among other things.

Upon curing the polysilocarb precursor formulation a cross linkingreaction takes place that provides in some embodiments a cross-linkedstructure having, among other things, an —R₁—Si—C—C—Si—O—Si—C—C—Si—R₂—where R₁ and R₂ vary depending upon, and are based upon, the precursorsused in the formulation. In an embodiment of the cured materials theymay have a cross-linked structure having 3-coordinated silicon centersto another silicon atom, being separated by fewer than 5 atoms betweensilicons.

During the curing process some formulations may exhibit an exotherm,i.e., a self heating reaction, that can produce a small amount of heatto assist or drive the curing reaction, or that may produce a largeamount of heat that may need to be managed and removed in order to avoidproblems, such as stress fractures. During the cure off gassingtypically occurs and results in a loss of material, which loss isdefined generally by the amount of material remaining, e.g., cure yield.Embodiments of the formulations, cure conditions, and polysilocarbprecursor formulations of embodiments of the present inventions can havecure yields of at least about 90%, about 92%, about 100%. In fact, withair cures the materials may have cure yields above 100%, e.g., about101-105%, as a result of oxygen being absorbed from the air.Additionally, during curing the material typically shrinks, thisshrinkage may be, depending upon the formulation, cure conditions, andthe nature of the preform shape, and whether the preform is reinforced,filled, neat or unreinforced, from about 20%, less than 20%, less thanabout 15%, less than about 5%, less than about 1%, less than about 0.5%,less than about 0.25% and smaller.

Curing of the preform may be accomplished by any type of heatingapparatus, or mechanisms, techniques, or morphologies that has therequisite level of temperature and environmental control, for example,heated water baths, electric furnaces, microwaves, gas furnaces,furnaces, forced heated air, towers, spray drying, falling filmreactors, fluidized bed reactors, lasers, indirect heating elements,direct heating, infrared heating, UV irradiation, RF furnace, in-situduring emulsification via high shear mixing, in-situ duringemulsification via ultrasonication.

The cured preforms, either unreinforced, neat, filled or reinforced, maybe used as a stand alone product, an end product, a final product, or apreliminary product for which later machining or processing may beperformed on. The preforms may also be subject to pyrolysis, whichconverts the preform material into a ceramic.

In pyrolizing the preform, or cured structure, or cured material, it isheated to about 600° C. to about 2,300° C.; from about 650° C. to about1,200° C., from about 800° C. to about 1300° C., from about 900° C. toabout 1200° C. and from about 950° C. to 1150° C. At these temperaturestypically all organic structures are either removed or combined with theinorganic constituents to form a ceramic. Typically at temperatures inthe about 650° C. to 1,200° C. range the resulting material is anamorphous glassy ceramic. When heated above about 1,200° C. the materialtypically may from nano crystalline structures, or micro crystallinestructures, such as SiC, Si3N₄, SiCN, β SiC, and above 1,900° C. an aSiC structure may form, and at and above 2,200° C. a SiC is typicallyformed. The pyrolized, e.g., ceramic materials can be single crystal,polycrystalline, amorphous, and combinations, variations and subgroupsof these and other types of morphologies.

The pyrolysis may be conducted under may different heating andenvironmental conditions, which preferably include thermo control,kinetic control and combinations and variations of these, among otherthings. For example, the pyrolysis may have various heating ramp rates,heating cycles and environmental conditions. In some embodiments, thetemperature may be raised, and held a predetermined temperature, toassist with known transitions (e.g., gassing, volatilization, molecularrearrangements, etc.) and then elevated to the next hold temperaturecorresponding to the next known transition. The pyrolysis may take placein reducing atmospheres, oxidative atmospheres, low O₂, gas rich (e.g.,within or directly adjacent to a flame), inert, N₂, Argon, air, reducedpressure, ambient pressure, elevated pressure, flowing gas (e.g., sweepgas, having a flow rate for example of from about from about 15.0 GHSVto about 0.1 GHSV, from about 6.3 GHSV to about 3.1 GHSV, and at about3.9 GHSV), static gas, and combinations and variations of these.

The pyrolysis is conducted over a time period that preferably results inthe complete pyrolysis of the preform. For high purity materials, thefurnace, containers, handling equipment, and other components of thepyrolysis apparatus are clean, essentially free from, free from and donot contribute any elements or materials, that would be consideredimpurities or contaminants, to the pyrolized material. A constant flowrate of “sweeping” gas can help purge the furnace during volatilegeneration. In an embodiment, the pyrolysis environment, e.g., thefurnace, the atmosphere, the container and combinations and variationsof these, can have materials that contribute to or effect, for example,the composition, stoichiometry, features, performance and combinationsand variations of these in the ceramic and the final applications orproducts.

During pyrolysis material may be lost through off gassing. The amount ofmaterial remaining at the end of a pyrolysis step, or cycle, is referredto as char yield (or pyrolysis yield). The formulations and polysilocarbprecursor formulations of embodiments of the present formulations canhave char yields for SiOC formation of at least about 60%, about 70%,about 80%, and at least about 90%, at least about 91% and greater. Infact, with air pyrolysis the materials may have char yields well above91%, which can approach 100%. In order to avoid the degradation of thematerial in an air pyrolysis (noting that typically pyrolysis isconducted in inert atmospheres, reduced oxygen atmosphere, essentiallyinert atmosphere, minimal oxygen atmospheres, and combinations andvariations of these) specifically tailored formulations can be used. Forexample, formulations high in phenyl content (at least about 11%, andpreferably at least about 20% by weight phenyls), formulations high inallyl content (at least about 15% to about 60%) can be used for airpyrolysis to mitigate the degradation of the material.

The initial or first pyrolysis step for SiOC formation, in someembodiments and for some uses, generally yields a structure that is notvery dense, and for example, may not reached the density required forits intended use. However, in some examples, such as the use oflightweight spheres, proppants, pigments, and others, the firstpyrolysis may be, and is typically sufficient. Thus, generally areinfiltration process may be performed on the pyrolized material, toadd in additional polysilocarb precursor formulation material, to fillin, or fill, the voids and spaces in the structure. This reinfiltratedmaterial may then be cured and repyrolized. (In some embodiments, thereinfiltrated materials is cured, but not pyrolized.) This process ofpyrolization, reinfiltration may be repeated, through one, two, three,and up to 10 or more times to obtain the desired density of the finalproduct.

In some embodiments, upon pyrolization, graphenic, graphitic, amorphouscarbon structures and combinations and variations of these are presentin the Si—O—C ceramic. A distribution of silicon species, consisting ofSiOxCy structures, which result in SiO4, SiO3C, SiO2C2, SiOC3, and SiC4are formed in varying ratios, arising from the precursor choice andtheir processing history. Carbon is generally bound between neighboringcarbons and/or to a Silicon atom. In general, in the ceramic state,carbon is largely not coordinated to an oxygen atom, thus oxygen islargely coordinated to silicon

The pyrolysis may be conducted in any heating apparatus that maintainsthe request temperature and environmental controls. Thus, for examplepyrolysis may be done with gas fired furnaces, electric furnaces, directheating, indirect heating, fluidized beds, kilns, tunnel kilns, boxkilns, shuttle kilns, coking type apparatus, lasers, microwaves, andcombinations and variations of these and other heating apparatus andsystems that can obtain the request temperatures for pyrolysis.

Custom and predetermined control of when chemical reactions,arrangements and rearrangements, occur in the various stages of theprocess from raw material to final end product can provide for reducedcosts, increased process control, increased reliability, increasedefficiency, enhanced product features, increased purity, andcombinations and variation of these and other benefits. The sequencingof when these transformations take place can be based upon theprocessing or making of precursors, and the processing or making ofprecursor formulations; and may also be based upon cure and pyrolysisconditions. Further, the custom and predetermined selection of thesesteps, formulations and conditions, can provide enhanced product andprocessing features through the various transformations, e.g., chemicalreactions; molecular arrangements and rearrangements; and microstructurearrangements and rearrangements.

At various points during the manufacturing process, the polymer derivedceramic structures, e.g., polysilocarb structures, intermediates and endproducts, and combinations and variations of these, may be machined,milled, molded, shaped, drilled, etched, or otherwise mechanicallyprocessed and shaped.

Starting materials, precursor formulations, polysilocarb precursorformulations, as well as, methods of formulating, making, forming,curing and pyrolizing, precursor materials to form polymer derivedmaterials, structures and ceramics, are set forth in Published US PatentApplications, Publication Nos. 2014/0274658, 2014/0343220, 2014/0326453and 2015/0175750 and US Patent Application Ser. Nos. 62/106,094 and62/193,046, the entire disclosures of each of which are incorporatedherein by reference.

Preferred SiOC Derived SiC Curing and Pyrolysis

Preferably, in making SiC, and materials for use in making SiC, in apreferred embodiment the polysilocarb precursors can be mixed at about 1atmosphere, in cleaned air.

Preferably, in making SiC, and materials for use in making SiC, thecuring takes place at temperatures in the range of from about 20° C. toabout 150° C., from about 75° C. to about 125° C. and from about 80° C.to 90° C. The curing is conducted over a time period that preferablyresults in a hard cured material. The curing can take place in air or aninert atmosphere, and preferably the curing takes place in an argonatmosphere at ambient pressure. Most preferably, for high puritymaterials, the furnace, containers, handling equipment, and othercomponents of the curing apparatus are clean, essentially free from, anddo not contribute any elements or materials, that would be consideredimpurities or contaminants, to the cured material.

Preferably, in making SiC, and materials for use in making SiC, thepyrolysis takes place at temperatures in the range of from about 800° C.to about 1300° C., from about 900° C. to about 1200° C. and from about950° C. to 1150° C. The pyrolysis is conducted over a time period thatpreferably results in the complete pyrolysis of the preform. Preferablythe pyrolysis takes place in inert gas, e.g., argon, and more preferablyin flowing argon gas at or about at atmospheric pressure. The gas canflow from about 1,200 cc/min to about 200 cc/min, from about 800 cc/minto about 400 cc/min, and at about 500 cc/min. Preferably, an initialvacuum evacuation of the processing furnace is completed to a reducedpressure at least below 1E-3 Torr and re-pressurized to greater than 100Torr with inert gas, e.g., Argon. More preferably, the vacuum evacuationis completed to a pressure below 1E-5 Torr prior to re-pressurizing withinert gas. The vacuum evacuation process can be completed anywhere fromzero to >4 times before proceeding. Most preferably, for high puritymaterials, the furnace, containers, handling equipment, and othercomponents of the curing apparatus are clean, essentially free from,free from and do not contribute any elements or materials, that would beconsidered impurities or contaminants, to the cured material.

In embodiments were low N and O levels are required, the use of avacuum, preferably a turbopump, to achieve 10E-6 Torr and backfillingwith inert gas is preferable. This purging process can be done once, ormultiple times, to achieve low levels. A constant flow rate of“sweeping” gas can help purge the furnace during volatile generation.

Preferably, in making SiC, the ceramic SiOC is converted to SiC insubsequent or continued pyrolysis or conversion steps. The conversionstep from SiOC may be a part of, e.g., continuous with, the pyrolysis ofthe SiOC preform, or it may be an entirely separate step in time,location and both. Depending upon the type of SiC desired the conventionstep can be carried out from about 1,200° C. to about 2,550° C. and fromabout 1,300° C. to 1,700° C. Generally, at temperatures from about1,600° C. to 1900° C., the formation of beta types is favored over time.At temperatures above 1900° C., the formation of alpha types is favoredover time. Preferably the conversion takes place in an inert gas, e.g.,argon, and more preferably in flowing argon gas at or about atatmospheric pressure. The gas can flow from about 600 cc/min to about 10cc/min, from about 300 cc/min to about 50 cc/min, and at about 80 cc/minto about 40 cc/min. Most preferably, for high purity materials, thefurnace, containers, handling equipment, and other components of thecuring apparatus are clean, essentially free from, and do not contributeany elements or materials, that would be considered impurities orcontaminants, to the SiC.

The subsequent yields for SiOC derived SiC are generally from about 10%to 50%, typically from 30% to 40%, although higher and lower ranges maybe obtained.

Most preferably, when making high purity SiC, the activities associatedwith making, curing, pyrolizing and converting the material areconducted in, under, clean room conditions, e.g., under an ISO 14644-1clean room standard of at least ISO 5, of at least ISO 4, of at leastISO 3, of at least ISO 2, and at least ISO 1. In an embodiment thematerial handling steps are conducted in the cleanroom of at least ISO5, while a less clean area (ISO >5) is used for the pyrolysis andconversion steps.

The following examples are provided to illustrate various embodimentsof, among other things, precursor formulations, processes, methods,apparatus, articles, compositions, and applications of the presentinventions. These examples are for illustrative purposes, and should notbe viewed as, and do not otherwise limit the scope of the presentinventions. The percentages used in the examples, unless specifiedotherwise, are weight percent of the total batch, preform or structure.

EXAMPLES Example 1

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together, at room temperature, 41% MHFand 59% TV. This precursor formulation has 0.68 moles of hydride, 0.68moles of vinyl, and 1.37 moles of methyl. The precursor formulation hasthe following molar amounts of Si, C and O based upon 100 g offormulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.37 25% C 2.74 50% O 1.37 25%

As calculated, the SiOC derived from this formulation will have acalculated 1.37 moles of C after all CO has been removed, and has 0%excess C.

Example 2

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together, at room temperature, 90%methyl terminated phenylethyl polysiloxane. (having 27% X) and 10% TV.This precursor formulation has 1.05 moles of hydride, 0.38 moles ofvinyl, 0.26 moles of phenyl, and 1.17 moles of methyl. The precursorformulation has the following molar amounts of Si, C and O based upon100 g of formulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.17 20% C 3.47 60% O 1.17 20%

As calculated, the SiOC derived from this formulation will have acalculated 2.31 moles of C after all CO has been removed, and has 98%excess C.

Example 3

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 70%methyl terminated phenylethyl polysiloxane (having 14% X) and 30% TV.This precursor formulation has 0.93 moles of hydride, 0.48 moles ofvinyl, 0.13 moles of phenyl, and 1.28 moles of methyl. The precursorformulation has the following molar amounts of Si, C and O based upon100 g of formulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.28 23% C 3.05 54% O 1.28 23%

As calculated, the SiOC derived from this formulation will have acalculated 1.77 moles of C after all CO has been removed, and has 38%excess C.

Example 4

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 50%methyl terminated phenylethyl polysiloxane (having 20% X) and 50% TV.This precursor formulation has 0.67 moles of hydride, 0.68 moles ofvinyl, 0.10 moles of phenyl, and 1.25 moles of methyl. The precursorformulation has the following molar amounts of Si, C and O based upon100 g of formulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.25 22% C 3.18 56% O 1.25 22%

As calculated, the SiOC derived from this formulation will have acalculated 1.93 moles of C after all CO has been removed, and has 55%excess C.

Example 5

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 65%methyl terminated phenylethyl polysiloxane (having 40% X) and 35% TV.This precursor formulation has 0.65 moles of hydride, 0.66 moles ofvinyl, 0.25 moles of phenyl, and 1.06 moles of methyl. The precursorformulation has the following molar amounts of Si, C and O based upon100 g of formulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.06 18% C 3.87 54% O 1.06 28%

As calculated, the SiOC derived from this formulation will have acalculated 2.81 moles of C after all CO has been removed, and has 166%excess C.

Example 6

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 65% MHFand 35% dicyclopentadiene (DCPD). This precursor formulation has 1.08moles of hydride, 0.53 moles of vinyl, 0.0 moles of phenyl, and 1.08moles of methyl. The precursor formulation has the following molaramounts of Si, C and O based upon 100 g of formulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.08 18% C 3.73 64% O 1.08 18%

As calculated, the SiOC derived from this formulation will have acalculated 2.65 moles of C after all CO has been removed, and has 144%excess C.

Example 7

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 82% MHFand 18% dicyclopentadiene (DCPD). This precursor formulation has 1.37moles of hydride, 0.27 moles of vinyl, 0.0 moles of phenyl, and 1.37moles of methyl. The precursor formulation has the following molaramounts of Si, C and O based upon 100 g of formulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.37 25% C 2.73 50% O 1.37 25%

As calculated, the SiOC derived from this formulation will have acalculated 1.37 moles of C after all CO has been removed, and has 0%excess C.

Example 8

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 46% MHF,34% TV and 20% VT. This precursor formulation has 0.77 moles of hydride,0.40 moles of vinyl, 0.0 moles of phenyl, and 1.43 moles of methyl. Theprecursor formulation has the following molar amounts of Si, C and Obased upon 100 g of formulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.43 30% C 1.95 40% O 1.43 30%

As calculated, the SiOC derived from this formulation will have acalculated 0.53 moles of C after all CO has been removed, and has a 63%C deficit, or is 63% C starved.

Example 9

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 70% MHF,20% TV and 10% VT. This precursor formulation has 1.17 moles of hydride,0.23 moles of vinyl, 0.0 moles of phenyl, and 1.53 moles of methyl. Theprecursor formulation has the following molar amounts of Si, C and Obased upon 100 g of formulation.

Molar Ratio of Si, C, O (% of total moles in “Moles” Moles Column) Si1.53 31% C 1.87 38% O 1.53 31%

As calculated, the SiOC derived from this formulation will have acalculated 0.33 moles of C after all CO has been removed, and has a 78%C deficit, or is 78% C starved.

Example 10

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 95% MHFAND 5% TV.

Example 11

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 50%methyl terminated phenylethyl polysiloxane (having 20% X) and 50% TV 95%MHF.

Example 12

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 54%methyl terminated phenylethyl polysiloxane (having 25% X) and 46% TV.

Example 13

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together at room temperature 57%methyl terminated phenylethyl polysiloxane (having 30% X) and 43% TV.

Example 14

About 100 grams of a polysilocarb formulation is made. The formulationis blended at room temperature for 15 minutes and then 1% catalyst isadded and the mixture is stirred for another 10 minutes. The catalysthas 10 ppm Pt in a short chain vinyl terminated polysiloxane.

The formulation is poured into a Teflon (PTFE,polytetrafluoroehtylene)-coated aluminum foil pan and cured for 2.5hours at 90° C. in argon or air.

The cured polymer is mechanically broken into sizes that fit intoceramic boats (e.g., crucibles that are 3.5″ long×2.5″ wide×⅝″ deep);and is placed in those ceramic boats. The ceramic boats containing thecured polymer are heated in a stainless steel retort filled with argongas flowing at 500 cc/min as follows:

-   -   room temp to 82.2° C. at a heating rate of 82.2° C./hr, with a 1        hour hold at 82.2° C.;    -   82.2° C. to 182° C. at a heating rate of 48.9° C./hr, with a 1        hour hold at 182° C.;    -   182° C. to 210° C. at a heating rate of 48.9° C./hr, with a 2        hour hold at 210° C.;    -   210° C. to 1,100° C. at a heating rate of 115.6° C./hr, with a 2        hour hold at 1.10° C.; and,    -   cool furnace to 204.4° C. before opening.

The pyrolized material is placed in graphite boats, with the pyrolizedmaterial being in powder form or in chunks. The graphite boats areplaced into an alumina tube furnace with two end blocks of insulationand caps to allow gas in flow and waist gas outflow. Argon gas at a rateof 50 cc/min is flowed through the tube furnace. The material is thenheated to 1,650° C. over a 10 hour period (about 3° C./min heating rate)and is held at this temperature for an additional 10 hours. The furnaceis then slowly cooled to 700° C. over a 5 hour period, the furnace isthen cooled further, with the end caps being removed when thetemperature is at least below 300° C.

The resultant polysilocarb derived SiC is removed from the furnace.

Example 15

A polysilocarb formulation is made in a clean room environment usingglassware that has been cleaned so as to essentially remove allpotential impurities, including in particular Al, Fe, and B. Theformulation is blended at room temperature for about 10 to 20 minutesand then from 0.25% to 2% catalyst solution is added and the mixture isstirred for another 10 minutes. The catalyst solution has 10 ppm Pt. Thefinal catalyzed formulation has between 10 and 50 ppb Pt.

In the clean room environment, the formulation is placed into a PFA(perfluoroalkoxy polymer) bottle or jar, purged with argon, and lidclosed. The formulation is cured for from 1.5 hours to 4 hours at from75° C. to 160° C.

In the clean room environment, the cured polymer is placed into ceramiccrucibles. The filled crucibles are then covered with ceramic caps, andplaced in a ceramic retort filled with argon gas flowing at 500 cc/min.The crucibles, furnace and all associate apparatus and equipment areclean and essentially contaminate free; and in particular are such thatthey do not provide a source of Al or B. The crucibles are heated at arate of increase from about 30° C. to about 180° C./hr as follows:

-   -   room temp to 1,000° C. at a heating rate of 180° C./hr, with a 2        hour hold at 1,000° C.; and,    -   cool furnace to 204.4° C. before opening.

The pyrolized material is placed in graphite boats, with the pyrolizedmaterial being in powder form or in chunks. The graphite boats areplaced into an alumina tube furnace with two end blocks of insulationand caps to allow gas in flow and waste gas outflow. The crucibles,furnace and all associate apparatus and equipment are clean andessentially contaminate free; and in particular, are such that they donot provide a source of Al, Fe, or B. Argon gas at a rate of 50 cc/minis flowed through the tube furnace. The material is then heated to from1,400° C. to 1,650° C. over a from 7 to 15 hour period (about 3° C./minheating rate) and is held at this temperature for an additional 10hours. The furnace is then slowly cooled to 700° C. over a 5 hourperiod, the furnace is then cooled further, with the end caps beingremoved when the temperature is at least below 300° C.

The resultant polysilocarb derived SiC is removed from the furnace.

Example 15a

A process along the lines of Example 15 is carried out using a graphitevacuum-capable furnace with purified graphite insulation and ports toallow gas in flow and waste gas outflow/vacuum evacuation. Argon gas ata rate of between 1 and 6 volume exchanges of the hot zone per hour isthen flowed through the graphite furnace. The material is then heated tofrom 25° C. to 2100° C. This process can provide 6-nines pure, and purerSiC.

Example 15b

In a process similar to the processes of Examples 15 and 15a, theheating, cooling, and both rates during pyrolysis and during conversioncan be from about 1 C/min to about 30° C./min, about 3° C./min to about20° C./min, about 10° C./min to about 20° C./min, and slower and fasterrates, as well as combinations of varied rates, e.g., 1 hour at about 5C/min and 3 hours at about 10° C./min. The hold times a particularelevated temperature can be from about 0.25 hours to about 24 hours,about 1 hour to about 12 hours, about 3 hours to about 8 hours, lessthan 24 hours, less than 12 hours, less than 8 hours, longer and shortertimes may also be used, as well as combinations and variations of thehold times in a particular heating cycle.

Example 16

A polysilocarb formulation is made in a clean room environment usingglassware that has been cleaned so as to essentially remove allpotential impurities. The formulation is blended at room temperatureuntil evenly intermixed and then a catalyst is added and the mixture isfurther stirred to distribute the catalyst. The polysilocarb formulationis then processed into high purity SiC in a continuous process, asfollows.

In the clean room environment, the formulation is placed into a graphitecontainer and cured to a hard cure. Without removing the cured materialfrom the furnace, the cured material is transformed to SiOC and then toSiC. During these heatings an inert, non-reactive gas is flowed throughthe furnace, the cured polymer is placed into ceramic crucibles.(Although N₂ is at times viewed as inert, in the making of high puritySiOC and SiC, it is preferably avoided for us in pyrolysis or conversionheatings, because it can react with the Si, forming nitride-containingspecies such as: silicon oxynitride, silicon nitride, and siliconcarbonitrides, for example)

The resultant polysilocarb derived SiC is removed from the furnace.

Example 17

Turning to FIG. 5 there is provided a schematic perspective flow diagramof an embodiment of a system and method for making SiOC derived SiC, andfor making such materials in lower purity, and more preferably in higherpurity (e.g., 3-nines, 4-nines, 5-nines and more, and preferably 6-ninesor more). The lines, valves and interior surfaces of the systemcontaining the precursors and other materials are made from or coatedwith materials that will not contaminate, e.g., provide a source ofimpurities, the SiOC and derived SiC. Storage tanks 150 a, 150 b holdliquid polysilocarb precursors. In this embodiment one or both or noneof the precursors can be taken through a distillation apparatus 151 aand distillation apparatus 151 b, to remove any impurities from theliquid precursor. The liquid precursors are then transferred to a mixingvessel 152 where they are mixed to form a precursor batch and catalyzed.In a clean room environment 157 a the precursor batch is packaged intovessels 153 for placement in a furnace 154. The furnace 154 has sweepgas inlet 161 and off-gas take away line 162. The packaged and curedmaterial is then transferred under clean room conditions, to severalpyrolysis furnaces 155 a, 155 b, 155 c, where it is transitioned fromSiOC to SiC. The furnaces have sweep gas inlet lines 158 a, 158 b, 158 crespectively, and two off-gas take away lines 159 a and 160 a, 159 b and160 b, 169 c and 160 c respectively. The resultant SiOC derived SiC isthen package 156, in a clean room environment 157 b, for shipment to oruse in other processes. The off-gasses can be processed, cleaned andstarting materials recovered in the off-gas processing assembly 163having an inlet line 164, which collects the off-gasses from variousunits in the system.

Example 18

SiC made from the process of Example 16, is 99.999 pure and has an X-RayDiffraction spectrum of FIG. 6. The spectrum is based upon “Position [°2Theta](Copper)” where area 601 of the spectra corresponds to 7.551 [°];2.496[°], where area 602 of the spectra corresponds to 16.737[°];3.994[°], where area 603 of the spectra corresponds to 35.644[°]; Si C;1.498[°], where area 604 of the spectra corresponds to 41.357[°]; Si C;1.498[°], where area 605 of the spectra corresponds to 59.977[°]; Si C;1.498[°], where area 606 of the spectra corresponds to 71.730[°]; Si C;1.498[°], where area 607 of the spectra corresponds to 75.461 [°]; Si C;1.498[°], where area 608 of the spectra corresponds to 89.958[°]; Si C;1.498[°], where area 609 of the spectra corresponds to 100.722[°]; Si C;1.498[°], where area 610 of the spectra corresponds to 104.874[°]; Si C;1.997[°], and where area 611 of the spectra corresponds to 119.903[°];Si C; 1.498[°].

Example 19

A polysilocarb formulation having 40% MHF and 60% TV was mixed and a 2%Pt Catalyst. The catalyzed formulation had 97.4 ppb (parts per billion)Al, 108.6 ppb Fe, 214 ppb B, no measurable P, and 96 ppb Pt. Thecatalyzed formulation was poured into a graphite vessel, which wasplaced in tube furnace, having an aluminum tube, with a graphite inner.The furnace was heated at a rate of 3° C./min until the temperaturereached 1675° C., where the temperature was held for 10 hours. Argon wasflowed through the furnace during the entire heating procedure. The SiCobtained was 3 nines pure, (i.e., 99.9% pure), having the followingimpurities (in ppm): Al 9.8, Fe 3.4, B 4.1, P 0.97, Pt 30, Ca 70, Mg 70,Li 53, Na 26, Ni 1.5, V 0.3, Pr 0.35, Ce 0.08, Cr 0.67, S 0.18, As 0.5.

Example 20

The 3 nines pure SiC material of Example 19, is soaked in an acid wash(10% HNO3+5% HCl solution) and then deionized water rinsed. The washedSiC has a purity of 5 nines.

Example 21

The process of Example 19 was conducted under cleanroom conditions andprotocols. The alumina furnace tube was replaced with a ceramic furnace,B, Fe and P were removed from the starting materials, i.e., MHF and TVvia ion exchange resin such as Amberlite IRA743, stripped, or distilled.The resulting silicon Carbide is 5 nines pure.

Example 22

The SiC material of Example 21 is washed and rinsed and the cleanedmaterial is 6 nines pure.

Example 23

The starting materials initially have 500 ppb (parts per billion) Al,5,000 ppb Fe, 500 ppb B, 1,700 ppb P. Using a cleanroom conditions andprotocols for this example, the starting materials are cleaned byfiltration. A polysilocarb formulation having 40% MHF and 60% TV is madefrom the cleaned starting materials, mixed, and to which 0.25% PtCatalyst solution is added. The catalyzed formulation has less thanabout 50 ppb Al, less than about 50 ppb Fe, less than about 50 ppb B,less than and about 50 ppb P and about 96 ppb Pt. The catalyzedformulation is poured into a graphite vessel, which is placed in afurnace, having a ceramic interior. A shield is place in the furnace toat least partially separate the heating element from the graphitevessel. The furnace is heated at a rate of 2.5° C./min until thetemperature reaches 1700° C., where the temperature is held for 12hours. Argon is flowed through the furnace during the entire heatingprocedure. The SiC obtained is 5 nines pure, having the followingimpurities (in ppm): Al 2.1, Fe 0.58, B 0.24, P 0.97, Pt 0.41, Ca <0.5,Mg <0.05, Li <0.01, Na 0.09, Ni 1.5, V <0.01, Pr <0.05, Ce <0.05, Cr<0.1, S <0.1, As <0.5. The SiC is primarily beta type.

Example 24

The SiC material of Example 23 is washed and rinsed and the cleanedmaterial is 6 nines pure.

Example 25

Using a cleanroom conditions and protocols for this example, apolysilocarb formulation having 40% MHF and 60% TV is made from thecleaned starting materials, mixed, and to which a 0.25% Pt Catalyst isadded. The catalyzed formulation is poured into a graphite vessel, whichis placed in a furnace, having a ceramic interior. The furnace is heatedat a rate of 3° C./min until the temperature reaches 2250° C., where thetemperature is held for 12 hours. Argon is flowed through the furnaceduring the entire heating procedure. The SiC obtained is 6 nines pure.The SiC is alpha type.

Example 26

A polysilocarb formulation is made in a clean room environment usingglassware that has been cleaned so as to essentially remove allpotential impurities. The formulation is blended at room temperatureuntil evenly intermixed and then from a catalyst is added and themixture is further stirred to distribute the catalyst. The polysilocarbformulation is then processed into high purity SiOC in a continuousprocess, as follows.

In the clean room environment, the formulation is placed into a graphitecontainer and cured to a hard cure. Without removing the cured materialfrom the furnace, the cured material is transformed to SiOC. During thisheating an inert, non-reactive gas, e.g., Ar is flowed through thefurnace. The resultant polysilocarb derived SiOC is removed from thefurnace. It can be washed, and has a purity of about 99.9999 (e.g., 6nines), with levels of Al and B being less than 0.1 ppm. The SiOC isstored under cleanroom conditions and protocols to protect it fromcontamination for later use.

Example 27

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together 30% of the MHF precursorhaving a molecular weight of about 800 and 70% of the TV precursor allylterminated polydimethyl siloxane having a molecular weight of about 500are mixed together in a vessel and put in storage for later use formaking SiOC and SiC. The polysilocarb formulation has good shelf lifeand room temperature and the precursors have not, and do not react witheach other. The polysilocarb formulation has a viscosity of about 10cps.

Example 28

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together 10% of the MHF precursorhaving a molecular weight of about 800 and 73% of methyl terminatedphenylethyl polysiloxane (having 10% X) and a molecular weight of about1,000, and 16% of the TV precursor and 1% of the OH terminated precursorsilanol (hydroxy) terminated polydimethyl siloxane, having a molecularweight of about 1,000 are mixed together in a vessel and put in storagefor later use in making SiOC and SiC. The polysilocarb formulation hasgood shelf life and room temperature and the precursors have not, and donot react with each other. The polysilocarb formulation has a viscosityof about 18 cps.

Example 29

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together 0-90% of the MH precursorhaving a molecular weight of about 800, and 0-90% of the methylterminated phenylethyl polysiloxane (having 10% X) and a molecularweight of about 1000, and 0-30% of the TV precursor and 0-30% of thevinyl terminated precursor allyl terminated polydimethyl siloxane havinga molecular weight of about 9400 and 0-20% of the OH terminatedprecursor silanol (hydroxy) terminated polydimethyl siloxane, having amolecular weight of about 800 are mixed together in a vessel and put instorage for later use in forming SiOC and SiC. The polysilocarbformulation has good shelf life and room temperature and the precursorshave not, and do not react with each other. The polysilocarb formulationhas a viscosity of about 100 cps.

Example 30

A polysilocarb formulation using the mixing type method is formulated.The formulation is made by mixing together 20-80% of the MH precursorhaving a molecular weight of about 800, and 0-10% of the TV precursor,and 5-80% of the vinyl terminated precursor allyl terminatedpolydimethyl siloxane having a molecular weight of about are mixedtogether in a vessel and put in storage for later use to make SiOC andSiC. The polysilocarb formulation has good shelf life and roomtemperature and the precursors have not, and do not react with eachother. The polysilocarb formulation has a viscosity of about 300 cps.

Example 31

Using the reaction type process a precursor formulation was made usingthe following formulation. The temperature of the reaction wasmaintained at 61° C. for 21 hours.

Moles of % of Total % of Reactant/ Moles of Moles Moles Reactant orSolvent Mass Total MW solvent Silane of Si of EtOH Methyltriethoxysilane120.00 19.5% 178.30 0.67 47.43% 0.67 2.02 Phenylmethyldiethoxysilane0.00 0.0% 210.35 — 0.00% — — Dimethyldiethoxysilane 70.00 11.4% 148.280.47 33.27% 0.47 0.94 Methyldiethoxysilane 20.00 3.3% 134.25 0.15 10.50%0.15 0.30 Vinylmethyldiethoxysilane 20.00 3.3% 160.29 0.12 8.79% 0.120.25 Trimethyethoxysilane 0.00 0.0% 118.25 — 0.00% — — Hexane inhydrolyzer 0.00 0.0% 86.18 — Acetone in hydrolyzer 320.00 52.0% 58.085.51 Ethanol in hydrolyzer 0.00 0.0% 46.07 — Water in hydrolyzer 64.0010.4% 18.00 3.56 HCl 0.36 0.1% 36.00 0.01 Sodium bicarbonate 0.84 0.1%84.00 0.01

Example 32

Using the reaction type process a precursor formulation was made usingthe following formulation. The temperature of the reaction wasmaintained at 2° C. for 21 hours.

Moles of % of Total % of Reactant/ Moles of Moles Moles Reactant orSolvent Mass Total MW solvent Silane of Si of EtOH Phenyltriethoxysilane234.00 32.0% 240.37 0.97 54.34% 0.97 2.92 Phenylmethyldiethoxysilane90.00 12.3% 210.35 0.43 23.88% 0.43 0.86 Dimethyldiethoxysilane 0.000.0% 148.28 — 0.00% — — Methyldiethoxysilane 28.50 3.9% 134.25 0.2111.85% 0.21 0.42 Vinylmethyldiethoxysilane 28.50 3.9% 160.29 0.18 9.93%0.18 0.36 Trimethyethoxysilane 0.00 0.0% 118.25 — 0.00% — — Acetone inhydrolyzer 0.00 0.0% 58.08 — Ethanol in hydrolyzer 265.00 36.3% 46.075.75 Water in hydrolyzer 83.00 11.4% 18.00 4.61 HCl 0.36 0.0% 36.00 0.01Sodium bicarbonate 0.84 0.1% 84.00 0.01

Example 33

Using the reaction type process a precursor formulation was made usingthe following formulation. The temperature of the reaction wasmaintained at 61° C. for 21 hours.

Moles of % of Total % of Reactant/ Moles of Moles Moles Reactant orSolvent Mass Total MW solvent Silane of Si of EtOH Phenyltriethoxysilane142.00 21.1% 240.37 0.59 37.84% 0.59 1.77 Phenylmethyldiethoxysilane135.00 20.1% 210.35 0.64 41.11% 0.64 1.28 Dimethyldiethoxysilane 0.000.0% 148.28 — 0.00% — — Methyldiethoxysilane 24.00 3.6% 134.25 0.1811.45% 0.18 0.36 Vinylmethyldiethoxysilane 24.00 3.6% 160.29 0.15 9.59%0.15 0.30 Trimethyethoxysilane 0.00 0.0% 118.25 — 0.00% — — Acetone inhydrolyzer 278.00 41.3% 58.08 4.79 Ethanol in hydrolyzer 0.00 0.0% 46.07— Water in hydrolyzer 69.00 10.2% 18.00 3.83 HCl 0.36 0.1% 36.00 0.01Sodium bicarbonate 0.84 0.1% 84.00 0.01

Example 34

Using the reaction type process a precursor formulation was made usingthe following formulation. The temperature of the reaction wasmaintained at 61° C. for 21 hours.

Moles of % of Total % of Reactant/ Moles of Moles Moles Reactant orSolvent Mass Total MW solvent Silane of Si of EtOH Phenyltriethoxysilane198.00 26.6% 240.37 0.82 52.84% 0.82 2.47 Phenylmethyldiethoxysilane0.00 0.0% 210.35 — 0.00% — — Dimethyldiethoxysilane 109.00 14.6% 148.280.74 47.16% 0.74 1.47 Methyldiethoxysilane 0.00 0.0% 134.25 — 0.00% — —Vinylmethyldiethoxysilane 0.00 0.0% 160.29 — 0.00% — —Trimethyethoxysilane 0.00 0.0% 118.25 — 0.00% — — Acetone in hydrolyzer365.00 49.0% 58.08 6.28 Ethanol in hydrolyzer 0.00 0.0% 46.07 — Water inhydrolyzer 72.00 9.7% 18.00 4.00 HCl 0.36 0.0% 36.00 0.01 Sodiumbicarbonate 0.84 0.1% 84.00 0.01

Example 35

Using the reaction type process a precursor formulation was made usingthe following formulation. The temperature of the reaction wasmaintained at 61° C. for 21 hours.

Moles of % of Total % of Reactant/ Moles of Moles Moles Reactant orSolvent Mass Total MW solvent Silane of Si of EtOH Phenyltriethoxysilane0.00 0.0% 240.37 — 0.00% — — Phenylmethyldiethoxysilane 0.00 0.0% 210.35— 0.00% — — Dimethyldiethoxysilane 140.00 17.9% 148.28 0.94 58.38% 0.941.89 Methyldiethoxysilane 0.00 0.0% 134.25 — 0.00% — —Vinylmethyldiethoxysilane 0.00 0.0% 160.29 — 0.00% — — TES 40 140.0017.9% 208.00 0.67 41.62% 0.67 2.69 Hexane in hydrolyzer 0.00 0.0% 86.18— Acetone in hydrolyzer 420.00 53.6% 58.08 7.23 Ethanol in hydrolyzer0.00 0.0% 46.07 — Water in hydrolyzer 84.00 10.7% 18.00 4.67

Example 35

Turning to FIG. 7 there is shown a schematic cross sectionalrepresentation of an apparatus for growing SiC crystals and crystallinestructures. The vapor deposition device 700 has a vessel 701 that isassociated with, (e.g., thermally associated, positioned to deliverelectromagnetic energy, has wrapped around it) various heating elements,e.g., 702. The heating elements are configured and operated to provideat least two different temperature zones, Zone A, 702 a, and Zone B, 702b. Inside of the vessel 701 there is a polymer derived ceramic 703,which is a source of Si and C. Additionally, inside the vessel 701 is acrystal grown initiation article 704.

Thus, in general the polymer derived ceramic 703 is heated to atemperature in Zone A 702 a to cause the SiC to sublimate, generally atemperature greater than about 2,000° C. The Si C vapors then rise intotemperature Zone B, which is cooler than Zone A. The Si C vapors aredeposited on the initiation article 704 as SiC.

It being understood that the schematic of the device 700, is a teachingillustration, greatly simplified, and that commercial and industrialdevices can have additional components, such as control systems,monitors, gas handling and other devices and can also have differentconfigurations, presently known to those of skill in the art, as wellas, new devices and configurations that may be based, in part, upon theteachings of this specification.

Example 35a

In the vapor deposition device 701 the polymer derived ceramic 703 ishigh purity SiOC. The temperature of Zone A is gradually increased andheld at set temperatures to transition the SiOC to SiC and then to causethe SiC to sublimate and form an SiC crystal on the initiation article704.

Example 35b

In this example the initiation article 704 is a seed crystal and the SiCthat is deposited from the polymer derived SiC in Zone A form an alphamono-crystalline boule. This boule is then sectioned to formpolysilocarb derived SiC wafers.

Example 35c

In this example the initiation article 704 is a Si substrate and the SiCfrom the polymer derived SiC in Zone A is deposited on the substrate asan epitaxial polysilocarb derived SiC layer on the Si substrate.

Example 35d

In the vapor deposition device 701 the polymer derived ceramic 703 ishigh purity SiOC, having 6 nines purity. The temperature of Zone A isgradually increased and held at set temperatures to transition the SiOCto SiC and then to cause the SiC to sublimate and form an SiC crystal onthe initiation article 704.

Example 35e

In the vapor deposition device 701 the polymer derived ceramic 703 ishigh purity SiOC, having less than 20 ppm Al. The temperature of Zone Ais gradually increased and held at set temperatures to transition theSiOC to SiC and then to cause the SiC to sublimate and form an SiCcrystal on the initiation article 704.

Example 35f

In the vapor deposition device 701 the polymer derived ceramic 703 ishigh purity polysilocarb derived SiC, having less than 20 ppm Al. TheSiC sublimates to form a SiC crystal on the initiation article 704,which is a seed crystal.

Example 36

The vapor deposition device 701 is a hot wall reactor.

Example 37

The vapor deposition device 701 is a multiwafer reactor.

Example 38

The vapor deposition device 701 is a chimney reactor.

Example 39

A boule of polysilocarb derived SiC having a length of about 1 inch anda diameter of about 4 inches. The boule is alpha type and is free frommicropipes. The boule having less than 100, less than 10, and preferableno 1 micropores.

Example 39a

A boule of polysilocarb derived SiC has micropipe density of <10/cm²,<5/cm², <1/cm², <0.5/cm² and most preferably <0.1/cm².

Example 40

A metal-semiconductor filed effect transistor (MESFET) is made frompolysilocarb derived SiC. This MESFET is incorporated into compoundsemiconductor device, operating in the 45 GHz frequency range.

Example 41

A metal-semiconductor filed effect transistor (MESFET) is made frompolysilocarb derived SiC. This MESFET is incorporated into a componentof a cellular base station.

Example 42

A boule of polysilocarb derived SiC having a length of about 2 inchesand a diameter of about 4 inches. The boule is doped to form p wafersfor a semiconductor device.

Example 43

A boule of polysilocarb derived SiC having a length of about 2 inchesand a diameter of about 4 inches. The boule is doped to form n wafersfor a semiconductor device.

Example 44

Turning to FIG. 8 there is shown a schematic cross sectionalrepresentation of an apparatus for growing SiC crystals and crystallinestructures. The vapor deposition device 800 has a vessel 801 that isassociated with heat sources 802. The heat sources, and vessel and heatsources, can be any of the assemblies described in this specification orthat are know to the art. The heat sources are configured and operatedto provide at least two different temperature zones, Zone A, 802 a, andZone B, 802 b. Inside of the vessel 801 there is a polymer derivedceramic 803, which is a source of Si and C. The polymer derived ceramic803 is the polysilocarb of Example 6 that has been cured and transformedinto SiC according to Example 14. Additionally, inside the vessel 801 isa crystal grown initiation article 804.

Thus, in general the polymer derived ceramic 803 is heated to atemperature in Zone A 802 a to cause the SiC to sublimate, generally atemperature greater than about 2,400° C. The Si C vapors then rise intotemperature Zone B, which is cooler than Zone A. The Si C vapors aredeposited on the initiation article 804 as SiC.

It being understood that the schematic of the device 800, is a teachingillustration, greatly simplified, and that commercial and industrialdevices can have additional components, such as control systems,monitors, gas handling and other devices and can also have differentconfigurations, presently known to those of skill in the art, as wellas, new devices and configurations that may be based, in part, upon theteachings of this specification.

Example 45

Turning to FIG. 9 there is shown a schematic cross sectionalrepresentation of an apparatus for growing SiC crystals and crystallinestructures. The vapor deposition device 900 has a vessel 901 that isassociated with heat sources 902. The heat sources, and vessel and heatsources, can be any of the assemblies described in this specification orthat are know to the art. The heat sources are configured and operatedto provide at least two different temperature zones, Zone A, 902 a, andZone B, 902 b. Inside of the vessel 901 there is a polymer derivedceramic 903, which is a source of Si and C. The polymer derived ceramic903 is the polysilocarb of Example 7 that has been cured and transformedinto SiC according to Example 15. Additionally, inside the vessel 901 isa crystal grown initiation article 904.

Thus, in general the polymer derived ceramic 903 is heated to atemperature in Zone A 902 a to cause the SiC to sublimate, generally atemperature about 2,500° C. The Si C vapors then rise into temperatureZone B, which is cooler than Zone A. The Si C vapors are deposited onthe initiation article 904 as SiC.

It being understood that the schematic of the device 900, is a teachingillustration, greatly simplified, and that commercial and industrialdevices can have additional components, such as control systems,monitors, gas handling and other devices and can also have differentconfigurations, presently known to those of skill in the art, as wellas, new devices and configurations that may be based, in part, upon theteachings of this specification.

Example 46

It is theorized that excess or added carbon in the polysicocarb derivedSiC material functions as a sintering aid. Polysilocarb derived SiC,having a purity of at least about 7-nines, having at about 0.05% to 0.5%excess carbon, is formed into small particles, about 0.1 μm. Theseparticles are then sintered together to form a SiC article. Noadditional sintering aid is required to form a solid SiC article. This“carbon-sintered” article, is substantially stronger than a similararticle that is formed with the use of a traditional sintering aid.

Example 46a

Polysilocarb derived SiC having a purity of at least about 7-nines isformed into small particles, about 0.1 μm. These particles are thensintered together to form a SiC article. No additional sinter aid isrequired to to form a solid SiC article. This “self” sintered article,is substantially stronger than a similar article that is formed with theuse of a traditional sintering aid.

Example 47

High purity polysilocarb derived SiC is formed into small particles. Theparticle size is small enough so to not affect a preselected wavelength,or wavelength range, of light. The SiC particles are sintered togetherto form an optical element, that is transmissive to light at thepreselected wavelength.

Example 48

A block of polysilocarb derived SiC is porous. The block of polysilocarbmaterial is for use in a vapor deposition apparatus.

Example 49

A polysilocarb derived SiC particle that is essentially free from anoxide layer on its surface.

Example 50

A polysilocarb derived SiC high temperature field effect gas sensor,with the SiC semiconductor material having a band gap of about 3.2 eV.This sensor is capable of operating at temperatures as high as 1,000° C.

Example 51

A polysilocarb derived SiC GTO (gate turnoff thyristor) is a componentof a three-phase dc-ac inverter. This device can provide about 1,200-Vforward blocking voltage and a controllable density of 500 A/cm².

Example 52

Polysilocarb derived SiC particles, having an average diameter of lessthan 0.25 μm, (and preferably about 0.1 μm and smaller) are essentialfree from an oxide layer on their surface. The SiC particles being readyto press (RTP), e.g., they can be sintered into a volumetric shape withminimal use of sintering aids, and preferably without the need forsintering aids. The “self-sintered SiC article, is substantiallystronger than a similar SiC article that is formed with the use ofsintering aids.

Example 52a

The SiC particles of Example 52, in which the polysilocarb derived highpurity SiC particles are at least 5-nines pure, are sintered to form aSiC optic.

Example 52b

The SiC particles of Example 52, in which the polysilocarb derived highpurity SiC particles are at least 3-nines pure, are sintered to form aSiC wafer.

Example 52c

The SiC particles of Example 52, in which the polysilocarb derived highpurity SiC particles are 7-nines pure, are sintered to form a SiC wafer,preferably without the use of sintering aids.

Example 53

A precursor formulation was made using polymerization of 20 g oftetravinyltetramethylcyclotetrasiloxane with 0.5% of Luperox 231peroxide catalyst. The formulation was cured at 115° C. for 60 minutes.The cured polymer was converted to SiC at 1675° C. The final densitymeasured 3.2 g/cc.

Example 54

200 g of tetravinyltetramethylcyclotetrasiloxane was purified bydistillation prior to use. A precursor formulation was made using 20 gof distilled tetravinyltetramethylcyclotetrasiloxane and was catalyzedwith 0.5% of Luperox 231. The formulation was cured at 115° C. for 60minutes. The cured polymer was converted to SiC at 1675° C. The finaldensity measured 3.2 g/cc

Example 55

A precursor formulation was made using 2 g MH and 18 g of TV. 0.5% ofLuperox 231 was added, as well as 2 ppm Pt catalyst. The formulation wascured at 115° C. for 60 minutes. The cured polymer was converted to SiCat 1675° C. The final density measured 3.2 g/cc

Example 56

A precursor formulation was made using 99% MH and 1% of Pt catalystsolution (10 ppm). The formulation was cured at 115° C. for 60 minutesand pyrolized to 1000° C. for 2 hours.

Example 57

A peroxide catalyst is added to the polysilocarb formulation of Examples1-3 and these catalyzed formulations are added drop wise (e.g., drops ofthe formulation are dropped into) to a 50-120° C. hot water bath to curethe formulation. The time in the hot water bath was about 1-2 minutes.The cured drop structures were then pyrolized at 950° C. for about 60minutes. The pyrolized structures were hollow spheres with densities ofless than about 1 g/cc, diameters of about 60 microns to about 2 mm, andcrush strengths of about 0.5-2 ksi. These hollow spheres are then milledto a size of less than 1 micron.

Example 58

10 ppm of a platinum catalyst is added to each of the polysilocarbbatches of Examples 4-10 and these catalyzed batches are dropped on atray to form droplets and are cured in an air oven at about 125° C. forabout 30 minutes. The cured drop structures were slightly non-roundbeads with densities of about 1.1-1.7 g/cc, diameters of about 200microns to about 2 mm, and crush strengths of about 3-7 ksi.

Example 59

A peroxide catalyzed polysilocarb batch is added to a water bath at50-95° C., under strong agitation and preferably in the presence of asurfactant, which more preferably does not constitute an impurity. Greencured submicron beads (e.g., <1 μm) that are formed in the water bathare then removed from the water bath. The green cured beads are then,cured, pyrolized and converted to SiC.

Example 60

A peroxide catalyzed polysilocarb batch is added to a water bath at50-95° C., under strong agitation and preferably in the presence of asurfactant, which more preferably does not constitute an impurity. Greencured beads that are formed in the water bath are then removed from thewater bath. The green cured beads may then be removed from the water, orkept in the water, for later use, e.g., conversion to SiC.

Example 61

A peroxide catalyzed polysilocarb batch, from Examples 1-13, is added toa water bath at 80° C., under strong agitation and preferably in thepresence of a surfactant, which more preferably does not constitute animpurity. Green cured 2 μm beads that are formed in the water bath arethen removed from the water bath. The green cured beads are then, cured,and pyrolized.

Example 62

A platinum catalyzed polysilocarb batch, from Examples 1-13, is added toa water bath at 100° C., under agitation. Green cured 2 mm beads thatare formed in the water bath are then removed from the water bath. Thegreen cured beads are then, cured, pyrolized and converted to SiC.

Example 63

A peroxide catalyzed polysilocarb batch is added to a water bath at50-95° C., under strong agitation and preferably in the presence of asurfactant, which more preferably does not constitute an impurity. Greencured 5 μm beads (e.g., <1) that are formed in the water bath are thenremoved from the water bath. The green cured beads are then, cured,pyrolized and converted to SiC.

Example 64

A peroxide catalyzed polysilocarb batch is added to a water bath at 95°C., under strong agitation and preferably in the presence of asurfactant, which more preferably does not constitute an impurity. Greencured beads that are formed in the water bath are then removed from thewater bath. The green cured beads may then be removed from the water, orkept in the water, for later use, e.g., conversion to SiC.

Example 65

A peroxide catalyzed polysilocarb batch, from Examples 1-13, is added toa water bath at 80° C., under strong agitation and preferably in thepresence of a surfactant, which more preferably does not constitute animpurity. Green cured 2 μm beads that are formed in the water bath arethen removed from the water bath. The green cured beads are then, cured,pyrolized and converted to SiC.

Example 66

A platinum catalyzed polysilocarb batch, from Examples 1-13, is added toa water bath at 100° C., under agitation. Green cured 2 mm beads thatare formed in the water bath are then removed from the water bath. Thegreen cured beads are then, cured, pyrolized and converted to SiC.

Example 67

Polysilocarb derived SiC particles, having an average diameter of about0.4 μm, are essential free from an oxide layer on their surface. The SiCparticles being ready to press (RTP), e.g., they can be sintered into avolumetric shape with minimal use of sintering aids, and preferablywithout the need for sintering aids.

Example 68

Polysilocarb derived SiC particles, having an average diameter of about0.6 μm, are essential free from an oxide layer on their surface. The SiCparticles being ready to press (RTP), e.g., they can be sintered into avolumetric shape with minimal use of sintering aids, and preferablywithout the need for sintering aids.

Example 69

Polysilocarb derived SiC particles, having an average diameter of about0.4 to 0.6 μm, are essential free from an oxide layer on their surface.The SiC particles being ready to press (RTP), e.g., they can be sinteredinto a volumetric shape with minimal use of sintering aids, andpreferably without the need for sintering aids.

Example 70

A blast and impact shield is formed using one of more layers of highpurity polysilocarb silicon carbide sintered into a sheet material.Layers of polysilocarb derived silicon carbide sheets are bonded to asubstrate. The layers are reinforced and can be done so with variedweave patterns between the layers. The composite layers structureprovides protection against blasts, projectiles and explosions. Thisshield can weigh less than conventional shields and armor, whileproviding equal or better protection.

Example 71

A blast and impact shield is formed using one of more layers of highpurity polysilocarb silicon carbide, having 6-nines purity, no oxygen,and a particle size of 0.1 microns is sintered, without the need for asintering aid, into a sheet material. The polysilocarb derived siliconcarbide sheets are used as a component in a blast and impact shield.That may be used in personal body armor and vehicle armor.

Example 72

A ballistic composite structure has 12 Layers of 1200 g/sq. meterfiberglass, 20 layers of unidirectional carbon fiber oriented at 0, 45,−45, 90 in 5 sections to make 20 layers, and 1 layer of polysilocarbderived silicon carbide as face sheet. The fiberglass can be bondedtogether using, a polysilocarb batch, and a warm press at 150-160 C for1-2 hours and a minimum of 500 psi pressure to form a fiberglass plate.The 20 layers of carbon fiber cloth can be bonded together under sameconditions to form a carbon fiber plate. The fiberglass plate, thecarbon fiber plate and the polysilocarb silicon carbide derived sheetare bonded in one step using a polysilocarb batch as the bonder betweenthe silicon carbide sheet and the carbon fiber plate and between thecarbon fiber plate and the fiberglass plate.

Example 73

Ultra pure SiOC, of the formulations provided in this specification andhaving at least about 5-nines, and preferably about 6-nines purity, isused to make transparent SiOC articles in the processes disclosed andtaught in U.S. Pat. No. 5,180,694, the entire disclosure of which isincorporated herein by reference.

Example 74

Ultra pure SiOC, of the formulations provided in this specification andhaving at least about 5-nines, and preferably about 6-nines purity isused to make SiOC layers and coatings on articles and in the processesdisclosed and taught in U.S. Pat. No. 8,981,564.

Example 75

Ultra pure SiOC, of the formulations provided in this specification andhaving at least about 5-nines, and preferably about 6-nines purity isused to make SiOC layers and coatings on articles and in the processesdisclosed and taught in U.S. Pat. No. 8,778,814.

It is noted that there is no requirement to provide or address thetheory underlying the novel and groundbreaking processes, materials,performance or other beneficial features and properties that are thesubject of, or associated with, embodiments of the present inventions.Nevertheless, various theories are provided in this specification tofurther advance the art in this area. These theories put forth in thisspecification, and unless expressly stated otherwise, in no way limit,restrict or narrow the scope of protection to be afforded the claimedinventions. These theories many not be required or practiced to utilizethe present inventions. It is further understood that the presentinventions may lead to new, and heretofore unknown theories to explainthe function-features of embodiments of the methods, articles,materials, devices and system of the present inventions; and such laterdeveloped theories shall not limit the scope of protection afforded thepresent inventions.

The various embodiments of formulations, batches, materials,compositions, devices, systems, apparatus, operations activities andmethods set forth in this specification may be used in the variousfields where SiC and Si find applicability, as well as, in other fields,where SiC, Si and both, have been unable to perform in a viable manner(either cost, performance or both). Additionally, these variousembodiments set forth in this specification may be used with each otherin different and various combinations. Thus, for example, theconfigurations provided in the various embodiments of this specificationmay be used with each other; and the scope of protection afforded thepresent inventions should not be limited to a particular embodiment,configuration or arrangement that is set forth in a particularembodiment, example, or in an embodiment in a particular Figure.

The inventions may be embodied in other forms than those specificallydisclosed herein without departing from their spirit or essentialcharacteristics. The described embodiments are to be considered in allrespects only as illustrative and not restrictive.

1-18. (canceled)
 19. A sinterable silicon carbide compositioncomprising: a. a plurality of silicon carbide particles, the pluralityof particles having a total weight of greater than at least about 10grams; b. the particles having a mean particle size of about 0.5 μm orsmaller; c. the composition consisting essentially of silicon and carbonin an SiC₄ configuration, wherein the particles have less than 0.5%excess carbon, and are at least 99.99999% pure; d. wherein the particlesare capable of being sintered into a solid SiC article without the needfor a sintering aid, the sintered SiC article having at least onestrength properties at least 90% as strong as elemental SiC.
 20. Asilicon carbide composition comprising: a. polymer derived siliconcarbide particles; b. the particles having a mean particle size of about0.5 μm or smaller, each particle having a surface, wherein the surfacesare free from an oxide layer; c. the particles consisting essentially ofsilicon and carbon, wherein the particles have less than 0.5% excesscarbon, and are at least 99.99999% pure. 21-27. (canceled)